U.S. Commodity Futures Trading 

Commission 

Three Lafayette Centre 

1155 21st Street, NW 

Washington, D.C. 20581 

(202) 418-5000 

www.cftc.gov

U.S. Securities & Exchange Commission 

100 F Street, NE 

Washington, D.C. 20549 

(202) 551-5500 

www.sec.gov

Preliminary Findings Regarding

the Market Events of May 6, 2010

Report of the Staffs of the CFTC and SEC to the Joint Advisory Committee on

Emerging Regulatory Issues

May 18, 2010 

This is a report of preliminary findings by the staffs of the U.S. Commodity Futures 

Trading Commission and the U.S. Securities and Exchange Commission. The 

Commissions have expressed no view regarding the preliminary analysis or conclusions 

contained herein. 
 

i

Table of Contents

I. INTRODUCTION .............................................................................................................1

II. EXECUTIVE SUMMARY..............................................................................................2

III. GENERAL MARKET CONTEXT ............................................................................ 11

IV. PRELIMINARY FINDINGS ....................................................................................... 17

A. Securities Markets .............................................................................................. 17 

1. Broader Market Drop and Recovery................................................................. 17 

2. Securities that Suffered Declines Disproportionate to the Broader Market ..... 29 

B. Futures Markets.................................................................................................. 59 

1. Background....................................................................................................... 59 

2. Role of Liquidity in Markets............................................................................. 63 

3. Analysis of Large Traders................................................................................. 66 

4. Preliminary Findings......................................................................................... 69 

C. Clearance and Settlement................................................................................... 69 

1. Securities Markets............................................................................................. 69 

2. Futures Markets ................................................................................................ 70 

V. NEXT STEPS................................................................................................................... 72

A. Areas for Further Analysis ................................................................................ 72 

1. Securities Markets............................................................................................. 72 

2. Futures Markets ................................................................................................ 74 

3. Coordinated Analysis........................................................................................ 74 

B. Potential Regulatory Responses......................................................................... 75 

1. Securities Markets............................................................................................. 75 

2. Futures Markets ................................................................................................ 79 

APPENDIX A OVERVIEW OF THE SECURITIES MARKET STRUCTURE...A­1

APPENDIX B OVERVIEW OF THE FUTURES MARKET STRUCTURE .........B­1

APPENDIX C CROSS-MARKET CIRCUIT BREAKERS.........................................C-1 

APPENDIX D FUTURES MARKET INFORMATION...............................................D-1 

 
 

1

I. INTRODUCTION 

The Commodity Futures Trading Commission (“CFTC”) and the Securities and 

Exchange Commission (“SEC” and collectively, the “Commissions”) have established a 

Joint CFTC-SEC Advisory Committee on Emerging Regulatory Issues (the 

“Committee”). The establishment of the Committee was one of 20 recommendations 

included in the agencies’ joint harmonization report issued last year.1

The first item on the agenda of the Committee will be to conduct a review of the 

market events of May 6 and to make recommendations related to market structure and 

liquidity issues that may have contributed to the volatility experienced on that day, as 

well as disparate trading conventions and rules across various markets. 

This report to the Committee reflects the preliminary findings of the 

Commissions’ respective staffs resulting from their ongoing review of the events of May 

6. The report is intended to brief the Committee regarding the May 6 events and to 

provide certain context regarding the current structure of the equity and futures markets 

and the regulatory framework for those markets. 

This report includes: (a) an executive summary; (b) an overview providing 

general market context with respect to the events of May 6; (c) preliminary findings with 

respect to those events; and (d) areas for further analysis and initial next steps. In 

addition, this report contains several appendices providing relevant background regarding 

the market structure of the securities and futures markets. 

It is important to emphasize that the review of the events of May 6 is in its 

preliminary stages and is ongoing. The reconstruction of even a few hours of trading 

during an extremely active trading day in markets as broad and complex as ours—

involving thousands of products, millions of trades and hundreds of millions of data 

points—is an enormous undertaking. Although trading now occurs in microseconds, the 

framework and processes for creating, formatting, and collecting data across various 

types of market participants, products and trading venues is neither standardized nor fully 

automated. Once collected, this data must be carefully validated and analyzed. Such 

further data and analysis may substantially alter the preliminary findings presented in this 

report. The staffs of the Commissions therefore expect to supplement this report with 

further additional findings and analyses.

                                                       

1 Joint Report of the SEC and the CFTC on Harmonization of Regulation, October 16, 2009. 
 

2

II. EXECUTIVE SUMMARY 

 On May 6, 2010, the financial markets experienced a brief but severe drop in 

prices, falling more than 5% in a matter of minutes, only to recover a short time later. 

Since that day, the staffs of the Securities and Exchange Commission and the Commodity 

Futures Trading Commission have been collecting and reviewing massive amounts of 

information in order to understand the events and to recommend appropriate measures. 

SECURITIES MARKETS 

Preliminary Findings

 May 6 started with unsettling political and economic news from overseas 

concerning the European debt crisis that led to growing uncertainty in the financial 

markets. Increased uncertainty during the day is corroborated by various market data: 

high volatility; a flight to quality among investors; and the increase in premiums for 

buying protection against default by the Greek government. This led to a significant, but 

not extraordinary, down day in early trading for the securities and futures markets. 

Beginning shortly after 2:30 p.m.,2 however, this overall decline in the financial 

markets suddenly accelerated. Within a matter of a few minutes, there was an additional 

decline of more than five percent in both the equity and futures markets. This rapid 

decline was followed by a similarly rapid recovery. This extreme volatility in the 

markets suggests the occurrence of a temporary breakdown in the supply of liquidity 

across the markets. 

The decline and rebound of prices in major market indexes and individual 

securities on May 6 was unprecedented in its speed and scope. The whipsawing prices 

resulted in investors selling at losses during the decline and undermined confidence in the 

markets. Although evidence concerning the behavior of the financial markets on May 6, 

2010 continues to be collected and reviewed, a preliminary picture is beginning to 

emerge. 

At this point, we are focusing on the following working hypotheses and findings– 

(1) possible linkage between the precipitous decline in the prices of stock 

index products such as index ETFs and the E-mini S&P 500 futures, on 

the one hand, and simultaneous and subsequent waves of selling in 

individual securities, on the other, and the extent to which activity in one 

market may have led the others; 

(2) a generalized severe mismatch in liquidity, as evinced by sharply lower 

trading prices and possibly exacerbated by the withdrawal of liquidity by 

                                                       

2

 All times in this report are EDT. 
 

3

electronic market makers and the use of market orders, including 

automated stop-loss market orders designed to protect gains in recent 

market advances; 

(3) the extent to which the liquidity mismatch may have been exacerbated by 

disparate trading conventions among various exchanges, whereby trading 

was slowed in one venue, while continuing as normal in another; 

(4) the need to examine the use of “stub quotes”, which are designed to 

technically meet a requirement to provide a “two sided quote” but are at 

such low or high prices that they are not intended to be executed; 

(5) the use of market orders, stop loss market orders and stop loss limit orders 

that, when coupled with sharp declines in prices, for both equity and 

futures markets, might have contributed to market instability and a 

temporary breakdown in orderly trading; and 

(6) the impact on Exchange Traded Funds (ETFs), which suffered a 

disproportionate number of broken trades relative to other securities. 

We have found no evidence that these events were triggered by “fat finger” errors, 

computer hacking, or terrorist activity, although we cannot completely rule out these 

possibilities. 

Key Avenues for Further Investigation

Much work is needed to determine all of the causes of the market disruption on 

May 6. At this stage, however, there are a number of key themes that we are 

investigating. 

Futures and Cash Market Linkages. The first relates to the linkages between 

trading in equity index products, including stock index futures and the equity markets. 

About 250 executing firms processed transactions for thousands of accounts during the 

hour 2:00 p.m. – 3:00 p.m. in the E-Mini S&P 500 futures contract. Of these accounts, 

CFTC staff has more closely focused their examination to date on the top ten largest 

longs and top ten shorts. The vast majority of these traders traded on both sides of the 

market, meaning they both bought and sold during that period. One of these accounts 

was using the E-Mini S&P 500 contract to hedge and only entered orders to sell. That 

trader entered the market at around 2:32 and finished trading by around 2:51. The trader 

had a short futures position that represented on average nine percent of the volume traded 

during that period. The trader sold on the way down and continued to do so even as the 

price level recovered. This trader and others have executed hedging strategies of similar 

size previously.3

                                                       

3

 Statement of Gary Gensler, Chairman, Commodity Futures Trading Commission, Before the 

House of Representatives Committee on Financial Services, Subcommittee on Capital Markets, 

Insurance, and Government Sponsored Enterprises, May 11, 2010, at 8. Except as specifically 
 

4

Data from the CME order book indicates that, although trading volume in E-mini 

S&P 500 futures was very high on May 6, there were many more sell orders than there 

were buy orders from 2:30 p.m. to 2:45 p.m. The data also indicate that the bid ask 

spread widened significantly at or about 2:45 p.m. and that certain active traders partially 

withdrew from the market. Considerable selling pressure at this vulnerable period in time 

may have contributed to declining prices in the E-Mini S&P 500 – and other equivalent 

products such as the SPY (an ETF that tracks the S&P 500). 

All of these markets are closely linked by a complex web of traders and trading 

strategies. The precipitous decline in price in one market on May 6 may have influenced 

a sustained series of selling in other financial markets. The rapid rebound in price in one 

market could similarly have been linked to a rebound in price in another. 

Implications for the Equity Markets. The great majority of securities 

experienced declines that are generally consistent with the decline in value of the large 

indexes. Some were less than the approximately 5% decline in the E-mini S&P 500 

during that period, and some were greater. Approximately 86% of securities, however, 

reached lows for the day that were less than 10% away from the 2:40 p.m. price. 

The other 14% of securities suffered greater declines than the broader market, 

with some trading all the way down to one penny. The experience of these securities 

exposed potential weaknesses in the structure of the securities markets that must be 

addressed. 

One hypothesis as to why the prices of some securities declined by abnormally 

large amounts on May 6 is that they were affected by disparate practices among securities 

exchanges. In the U.S. securities market structure, many different trading venues, 

including multiple exchanges, alternative trading systems and broker-dealers all trade the 

same stocks simultaneously. Disparate practices potentially could have hampered 

linkages among these trading venues and led to fragmented trading in some securities. 

Two types of disparate practices on May 6 relate to the NYSE’s liquidity replenishment 

points (“LRPs”) and the self-help remedy in Regulation NMS. These and other practices 

merit significant ongoing review: 

● LRPs and Similar Practices. The NYSE’s trading system incorporates LRPs 

that are intended to dampen volatility. When an LRP is triggered, trading on 

the NYSE will “go slow” and pause for a time to allow additional liquidity to 

enter the market. Some have suggested that LRPs actually exacerbated, rather 

than dampened, price volatility on May 6 by causing a net loss of liquidity, as 

orders were routed to other trading venues for immediate execution rather 

than waiting on the LRP mechanism. If this occurred, it potentially could 

have caused some NYSE securities to decline further than the broad market 

decline. However, others believe that the LRP mechanism indeed dampened 

                                                                                                                                                                     authorized, Section 8 of the Commodity Exchange Act generally forbids disclosure of additional 

information regarding such traders. 
 

5

volatility by rebuilding additional buy side liquidity that soaked up some of 

the excess selling interest in these securities on May 6. LRPs and other types 

of exchange procedures for handling or executing orders will be closely 

examined to determine whether they inappropriately impede liquidity. 

● Self-Help Remedy. Another disparate exchange practice potentially relevant 

to the thinning of liquidity is the self-help remedy. Two exchanges declared 

self-help against NYSE Arca in the minutes prior to 2:40 p.m. Exchanges are 

entitled to exercise the self-help remedy when another exchange repeatedly 

fails to provide a response to incoming orders within one second. A 

declaration of self-help frees the declaring exchanges from their obligation to 

route orders to the affected exchange. Some have suggested the exercise of 

self-help led to a net loss of liquidity as the declaring exchanges stopped 

routing orders to NYSE Arca. 

● Stop Loss Market Orders. An additional hypothesis as to why some securities 

suffered more severe declines than the broader market on May 6 is that they 

were particularly affected by stop loss market orders. These orders have stop 

prices that, for sell orders, are lower than current prices. When the stop price 

is reached, such orders turn into market orders to sell. In fast-falling market 

conditions, stop loss market orders could potentially trigger a chain reaction of 

automated selling if they are in place in significant quantity for a particular 

stock. We are investigating whether such a chain reaction led to abnormally 

large declines for some stocks on May 6. 

• Short Sales and Stub Quotes. We also are examining the use of short sales 

and stub quotes on May 6. Our analysis thus far of broken trades has found 

that short sales accounted for approximately 70 % of executions against stub 

quotes between 2:45 p.m. and 2:50 p.m., and approximately 90 % of 

executions against stub quotes between 2:50 p.m. and 2:55 p.m. Notably, 

short sale executions against stub quotes would be subject to the alternative 

uptick rule (Rule 201) adopted by the SEC in February 2010, with a 

compliance date in November 2010. 

In addition, we will evaluate the use of stub quotes by market makers. As 

noted above, stub quotes are not intended to be executed and effectively 

indicate that the market maker has pulled out of the market. Their presence at 

the bottom and top of order books on May 6 may have led to a very large 

number of broken trades. We will examine the extent to which market makers 

used stub quotes to nominally meet their market making obligations on May 

6. 

Exchange-Traded Funds. Of the U.S.-listed securities with declines of 60% or 

more away from the 2:40 p.m. transaction prices, which resulted in their trades being 

cancelled by the exchanges, approximately 70% were ETFs. This suggests that ETFs as a 

class were affected more than any other category of securities. 
 

6

Based on our analysis to date, we are focused on a number of issues that may 

have contributed to the ETFs’ experience, including: 

• Because ETFs generally track securities market indices, the extraordinary 

price declines in certain individual securities likely contributed to the ETF 

price declines. For the most part, the severe ETF price declines followed, in 

time, the sharp decline in the broad markets. ETFs that track bond indices 

generally did not experience severe price declines. We therefore are 

considering the linkages between ETF price declines and the declines in the 

equity market. 

• The role of market makers and authorized participants in ETFs, and whether 

an inability to hedge their ETF positions during periods of severe volatility 

may have contributed to a lack of liquidity in ETF shares. 

• The use of ETFs by institutional investors as a way to quickly acquire (or 

eliminate) broad market exposures and whether this investment strategy led to 

substantial selling pressure on ETFs as the market began to decline 

significantly. 

• The impact of ETF stop loss market orders, particularly from retail investors, 

on the overall ETF market price declines. 

• Given that NYSE Arca is the primary listing exchange for almost all ETFs, 

whether the declaration of “self-help” against NYSE Arca by other exchanges 

may have impacted NYSE Arca-listed stocks generally and ETFs in 

particular. The loss of access to NYSE Arca’s liquidity pool may have had a 

greater impact on market liquidity and trading for ETFs. 

FUTURES MARKETS 

Preliminary Findings

Economic evidence from the futures markets is also consistent with the 

conclusion that a liquidity drain likely played a role in the dramatic and sudden 

movements in the price of stock index futures. 

As noted above, preliminary data indicates that, although trading volume in Emini S&P 500 futures was very high on May 6, there were many more sell orders than 

there were buy orders from 2:30 p.m. to 2:45 p.m. The data also indicate that the bid ask 

spread widened significantly at or about 2:45 p.m. and that certain active traders partially 

withdrew from the market. 

Starting at 2:45:28 p.m., CME’s Globex stop logic functionality initiated a brief 

pause in trading in the E-mini S&P 500 futures. This functionality is initiated when the 
 

7

last transaction price would have triggered a series of stop loss orders that, if executed, 

would have resulted in a cascade in prices outside a predetermined ‘no bust’ range (6 

points in either direction in the case of the E-mini). The purpose of this functionality is to 

prevent sudden, cascading declines (or increases) in price caused by order book 

imbalances. 

The stop logic functionality has been activated previously for a variety of 

instruments. In the case of the E-mini S&P 500 futures, the stop logic functionality has 

been triggered a number of times in the past few years, including several times during the 

financial crisis in the Fall of 2008, when market data indicates similar conditions as those 

seen on May 6. 

On May 6, activation of the stop logic functionality initiated a five second pause 

in trading on the E-mini S&P 500 futures contract. The price of the E-mini S&P 500 

futures rebounded after the five second pause imposed by the stop logic functionality. 

Staff analysis of market performance measures is consistent with the conclusion 

that a very temporary, but serious liquidity shortage occurred across the securities and 

futures markets. 

NEXT STEPS 

Securities Markets

SEC staff will continue our ongoing investigation of the nature of the overall 

market liquidity dislocation and the impact on individual stocks. Where appropriate we 

are moving quickly to prevent a recurrence of the harm that investors suffered on May 6. 

• We anticipate that the self-regulatory organizations (exchanges and FINRA) will 

propose circuit breakers for individual stocks that are designed to address 

temporary liquidity dislocation. Specifically, a pause in trading should provide an 

opportunity for all available sources of liquidity (both manual and automated) to 

be mobilized to meet sudden surges in demand for liquidity. 

• The procedures for breaking trades that occur at off-market prices should be 

improved to provide investors greater consistency, transparency and 

predictability. 

• We are also continuing to review a range of other policy options, including 

addressing the use of stub quotes, reviewing the obligations of professional 

liquidity providers and evaluating the use of various order types (market orders, 

stop loss orders). 
 

8

Futures Markets

CFTC staff will continue its analysis into the events of May 6. Specifically, 

CFTC staff is carefully reviewing the activity of the largest traders in stock index futures. 

CFTC staff will also continue its analysis, already begun by our Office of Chief 

Economist, of liquidity provision in futures markets, with a particular focus on electronic 

trading. The subjects to be reviewed here include high frequency and algorithmic 

trading, automatic execution innovations on trading platforms, market access issues, and 

co-location. 

CFTC staff is considering a proposed rulemaking with respect to exchange colocation and proximity hosting services. The purpose of the proposed rule would be to 

ensure that all otherwise qualified and eligible market participants that seek co-location 

or proximity hosting services offered by futures exchanges have equal access to such 

services without barriers that exclude access, or that bar otherwise qualified third-party 

vendors from providing co-location and/or proximity hosting services. Another purpose 

of the proposal would be to ensure that futures exchanges that offer co-location or 

proximity hosting services disclose publically the latencies for each available 

connectivity option, so that participants can make informed decisions. 

CFTC staff will also be considering possible rules to enhance the CFTC’s 

surveillance capabilities. These measures include automation of the statement of 

reporting traders in the large trader reporting system and obtaining account ownership 

and control information in the exchange trade registers.4

 These initiatives would increase 

the timeliness and efficiency of account identification, an essential step in data analysis. 

Joint Actions

• Staff also intends to pursue a joint study to examine the linkages between 

correlated assets in the equities (single stocks, mutual funds and ETFs), options 

and futures markets. The study could partly focus on examining cross-market 

linkages by analyzing trading in stock index products such as equity index 

futures, ETFs, equity index options, and equity index OTC derivatives using, to 

the extent practicable, market data, special call information, and order book data. 

• Existing cross-market circuit breaker provisions should be re-examined to ensure 

they continue to be effective in today’s fast paced electronic trading environment. 

Although the coordinated circuit breakers between futures and equities were not 

triggered, the events of May 6 reinforce the importance of having communication 

links between futures and equity markets so that there is meaningful and 

appropriate coordination of trading pauses and halts. 

                                                       

4

 17 CFR 18.04. 
 

9

PROCESS OF ANALYSIS 

Over the last ten days, the SEC and the CFTC have collected and analyzed a wide 

range of data from many different sources in order to prepare this preliminary report. 

Specifically: 

• The SEC has sourced and analyzed price, time, and volume data on over 19 

billion shares executed on May 6, and quote data representing the best bid and 

best offer for over 7,800 securities, for each exchange, for each millisecond 

during the trading day. Our goal is to gather data necessary to create a complete 

order book showing snap-shots of the full displayable depth on a particular market 

and audit trail data containing detailed information on all orders submitted. 

o Analysis of the complete order book is necessary to examine how changes 

in the provision of liquidity below the best bid, and above the best offer, 

led to rapid changes in execution prices, with some trades hitting high and 

low “stub quotes.” 

o Analysis of order audit trail data is necessary to examine what types of 

orders were driving these price swings (e.g., market, limit, etc). 

o The audit trail contains information on introducing brokers but does not 

include details regarding the trading activity of specific market 

participants. Currently, such data is only available directly from brokerdealers through “blue sheet” requests. Furthermore, even in this data 

participants are identified only in the way that they are known to the 

broker-dealer, as there are currently no uniform standards5

o The order book and order audit trail are maintained at exchanges, FINRA, 

broker-dealers and other market centers. In some cases this information 

must be collected by the SROs, and then must be compiled and organized 

by the SEC. Every exchange has established its own requirements for 

what constitutes an audit trail, including what items are captured, how 

they are named, and the structure of the data file. 

• The SEC has sourced and analyzed aggregate data on the volume and type of 

liquidity, provided and taken, by the largest liquidity providers and takers on 

various exchanges. 

• The SEC has worked extensively with the relevant securities exchanges and 

FINRA to assess the circumstances of the market events on May 6. In addition, 

the SEC is analyzing detailed data for all NYSE LRPs occurring on May 6th, as 

well as over the last 5 months. 

• CFTC staff has analyzed transaction and order book data on stock index futures, 

including the E-Mini S&P 500 futures contract. 

                                                       

5

 For example, the same market participant may be known to different broker-dealers by different 

names making the aggregation of orders for a single participant very difficult. For further details, 

see the SEC’s recent proposal for the Large Trader Reporting System. 
 

10

• CFTC staff has been reviewing information from a special call on over 40 large 

traders for their trading activity in the E-mini S&P 500 and Russell 2000 futures 

contracts on May 6, 2010. A special call is a CFTC directive to a trader holding a 

reportable position to furnish any pertinent information concerning the trader’s 

positions, transactions, or activities. 

• CFTC staff also has been reviewing information from a special call to swap 

dealers about their activity in over-the-counter broad-based security index 

derivatives markets on May 6, 2010. In addition, staff has been engaged in a 

detailed review of trader activity on May 6 through a comprehensive examination 

of trade-register data. To date, staff has received over 25 gigabytes of data in 

over 307,000 files, with more data expected. 

Both the CFTC and the SEC have had extensive conversations with a wide variety 

of market participants (investors, hedge funds, exchange traded funds, dealers, high 

frequency traders, etc.) to better understand their trading activities throughout May 6, and 

to gather anecdotal evidence from which common themes and/or trends can be identified 

to inform further areas of investigation. 
 

11

III. GENERAL MARKET CONTEXT 

 This section provides general market context for the trading activity on May 6. 

 Throughout the day on Thursday, May 6, many financial news outlets were 

reporting on political and economic events that were creating uncertainty in the financial 

markets. This increased uncertainty during that day is evidenced by patterns observable 

in financial market data. There is evidence of increasing volatility throughout the day, a 

“flight to quality”6

 (as seen in the rise in the price of gold and decline in U.S. Treasury 

yields), an increase in the price of premiums on credit default swaps to protect against the 

risk of default on European sovereign debt, and downward pressure on the Euro in global 

currency markets. All major broad-based equity indices and equity index futures spent 

much of the morning and early afternoon in negative territory (see chart below). For 

example, between 9:30 a.m. and 2:00 p.m., the Dow Jones Industrial Average (DJIA) 

declined 161 points to 10,712 (-1.5%), the S&P 500 Index declined 33 points to 1,145 

(-2.9%), and the E-mini S&P 500 Index June futures declined 15 points to 1,143 (-1.3%). 

Figure 1: Select Equity Indices and Equity Index Futures, May 6, 2010

Source: Bloomberg

                                                       

6

 Flight to Quality is a term used to describe the movement of capital into asset classes that are 

perceived to be less risky during times of financial uncertainty. 
 

12

Indicators of Market Uncertainty 

Market Volatility 

A general indicator of market uncertainty is the Chicago Board Options Exchange 

SPX Volatility Index (“VIX”). The VIX is a measure of the expected volatility of the 

S&P 500 index, based on options prices, and is sometimes colloquially referred to as the 

“fear index.” The VIX provides a picture of the expected range of S&P 500 index returns 

in the next 30 days. Higher values of the VIX imply a greater range of returns, both 

positive and negative. Thus, increases in the VIX signal increased uncertainty about 

possible stock returns. 

As seen in Figure 2, in 2010 the VIX prior to May 6 has averaged 19.58, a level 

that indicates much lower expected market volatility when compared to the VIX averages 

of 2008 (32.69) and 2009 (31.48). The elevated VIX levels from 2008 and 2009 were 

associated with a broader financial market crisis. Since then, the average level of the 

VIX has returned to levels that are consistent with the pre-2008 period. For example, in 

April the VIX averaged 17.42. For the month of May through May 14 the VIX has 

averaged28.33. 

Figure 2: Historical Daily VIX Values, January 2005 to May 2010

Source: Bloomberg

On May 6, the VIX opened at 25.88. This represents a 15.5% increase from when 

the trading week began on Monday, May 3 at 22.41. After staying level for most of the 

day, the VIX began to rise around 1:30 p.m. At 2:00 p.m. the VIX had increased 2.72 

points or 10.5% from its opening level, signaling increasing expected volatility in the 
 

13

S&P 500 Index. Over the next half-hour, the VIX steadily increased an additional 3.11 

points to 31.71, up 22.5% from the open. A nearly continuous rise in the VIX signals 

higher levels of expected market risk and uncertainty going forward. The increase in the 

VIX then accelerated and the index reached 40.26 by 2:46 p.m. Had markets closed at 

the 2:46 p.m. level of 40.26, it would have represented a 61.6% increase from the 

previous day’s close and would represent the fourth largest single-day increase in market 

volatility. Ultimately, the VIX closed at 32.80, a 31.7% increase from the previous day’s 

close.7

Figure 3: CBOE SPX Volatility Index Intraday Levels

Source: Bloomberg

Flight to Quality

Gold and U.S. Treasuries are assets that have historically been in high demand 

during periods of market uncertainty. On May 6, the COMEX nearby gold futures 

contract rose steadily from approximately $1,180 to $1,210 per troy ounce from the 

market open to its close at 1:30 p.m. Additionally, the ten-year Treasury yield fell from 

3.58% on May 5 to an intraday low of 3.26% before settling at 3.41% (see Figure 4). 

                                                       

7

 The three highest single-day increases in the VIX are 10/19/87 (312.95%), 10/13/89 (68.30%), and 

2/27/07 (64.22%). 
 

14

Figure 4: Ten­Year U.S. Treasury Note Yield

Source: Bloomberg

Credit Default Swaps 

The credit derivatives markets indicated increased uncertainty over the ability of 

the government of Greece to service its debt. Spreads on CDS protecting against the 

default of debt securities issued by Greece widened on May 6 to 937.9 basis points, up 

from 844.2 basis points the previous day.8 This essentially meant that the price of 

premiums to protect against a default by Greece had increased. This widening coincided 

with the European Central Bank’s press conference, beginning at 8:30a.m., in which the 

Bank did not address the possibility of purchasing Greek government bonds. Figure 5 

shows CDS spreads on Greek sovereign debt over the past five years. 

                                                       

8 A CDS spread widening means that it will cost more for a company to insure against default, 

because the market sees default as more likely than it previously did. In other words, someone 

who wants to buy protection on a risk of default of a debt has to pay a higher premium. 
 

15

Figure 5: Credit Default Spreads on Greek Sovereign Debt

Source: Bloomberg

Euro Declines Against the Dollar and Yen 

In addition, global currency markets were indicating concern over the financial 

stability of the European Union. Shortly after 1:00 p.m., the Euro began a sharp decline 

against both the U.S. Dollar and the Japanese Yen (see Figure 6). 
 

16

Figure 6: Euro­Dollar and Euro Yen Exchange Rates on May 6, 2010

Source: Bloomberg

Events During the Afternoon of May 6 

By approximately 2:45 p.m. over 200 securities had fallen 50% or more from 

their 2:00 p.m. levels. Between 2:45 p.m. and 2:47p.m., the DJIA, S&P 500, and 

NASDAQ100 all reached daily lows. During this same period, all 30 DJIA components 

reached their intraday minima, representing a range from -4% to -36% from their opening 

levels. The DJIA bottomed at 9,872.57, the S&P 500 at 1,065.79, and the NASDAQ100 

at 1,752.31. The E-mini S&P 500 index futures contract bottomed at 1,056. 

After bottoming, equity and equity index futures markets began to rebound. At 

2:50 p.m. the DJIA was trading at 10,232 and the E-mini S&P 500 was trading at 1,096. 

The E-mini S&P 500 climbed further to 1,118 by 2:53 p.m. The DJIA closed at 

10,520.32, down 347.68 points, or 3.2%, from the prior day’s close. The E-mini S&P 

500 settled at 1,122.5, down 41.5 points, or 3.6%, from the prior day’s settlement. 
 

17

IV.PRELIMINARY FINDINGS 

A. Securities Markets 

The market events of May 6, 2010 included a surge in trading in the stock 

markets, with total trading volume on that day of 19.4 billion shares, approximately 2.2 

times the average daily trading volume in the 4th quarter of 2009. The trading volume in 

NYSE-listed stocks across all trading venues on May 6 represented the second highest 

daily volume on record, while May 6 volume in NASDAQ-listed stocks across all trading 

venues was the highest on record. 

 The severe price decline and recovery that occurred during a period of 

approximately 20 minutes on the afternoon of May 6 can usefully be described in terms 

of two broad but related themes: (1) a precipitous drop in value of more than 5% 

followed immediately by a rapid recovery, both of which occurred consistently across 

various broad market indices and products; and (2) extreme price fluctuations – mostly 

losses – that occurred for certain individual securities, followed relatively promptly by 

reversions to price levels consistent with the broader market. These two themes are 

discussed below. 

1. Broader Market Drop and Recovery 

 On May 6, a wide variety of broad market indices and products displayed similar 

behavior – a severe price decline immediately followed by a rapid recovery during a 20-

minute period. This phenomenon is illustrated by the following price chart of the DJIA, 

the S&P 500 Index, and the E-mini S&P 500 futures (Figure 7). 

Figure 7: Equity Indices and Equity Index Futures
 

18

 Until approximately 2:40 p.m., the figure reflects a significant, but not 

extraordinary, down day that was influenced by multiple negative economic factors, as 

noted in the previous section. At approximately 2:40 p.m., however, prices declined with 

extraordinary velocity. Each of the indices fell in excess of 5% within 5 minutes, and 

then immediately began a recovery that exceeded 5% within 10 minutes. 

Most individual stocks declined by amounts that were generally consistent with 

the broader market decline. Approximately 86% of U.S.-listed securities reached lows 

for the day that were less than 10% away from the 2:40 p.m. price (a useful benchmark 

for the market price before the rapid market decline and recovery). The remaining 14% 

of U.S.-listed securities reached lows that exceeded 10% (these securities are discussed in 

greater detail in section IV.A.2 below). 

Figure 8:  Distribution of May 6 Daily Lows9

0

100

200

300

400

500

600

-100%

-95%

-90%

-85%

-80%

-75%

-70%

-65%

-60%

-55%

-50%

-45%

-40%

-35%

-30%

-25%

-20%

-15%

-10%

-5%

0%

Return from May 5 Close to May 6 Low

Number of Issues

Market Cap over $5 Billion

Market Cap between $500 Million and $5 Billion

Market Cap between $10 and $500 Million

Sources: Thomson Financial Datastream and NYSE Trades and Quotes.

                                                       

9

 This figure depicts the distribution of returns from the close on May 5 to the lowest transaction 

price on May 6. The securities included are equity securities (common and preferred) of corporate 

issuers, exchange-traded products, closed-end funds, and ADRs, traded on major U.S. exchanges, 

and having in each case, as of the May 5 close, a share price of more than $3.00 and a market 

capitalization of at least $10 million. 
 

19

Figure 8 illustrates in more detail the behavior of these two groups of individual 

securities. It shows that, for the day, there is a concentration of daily lows at a point near 

7% below the May 5 close, on the right-hand side of the graph. The distribution of lows 

for individual securities around this point is consistent with a day where the ETF that 

tracks the S&P 500 Index transacted 8.5% below the previous day’s close. The figure 

notably also shows that some securities exhibited substantially more pronounced daily 

lows than the decline in the broad market would imply. In particular, approximately 200 

securities traded, at their lows, almost 100% below their previous day’s values, as 

represented by the spike at the left-hand side of the graph. The incidence of extreme 

daily lows for large capitalization stocks (depicted on the graph in yellow) appears to be 

lower than for smaller capitalization stocks (depicted in the graph in purple). 

An examination of individual trades during the 2:40 p.m. - 3:00 p.m. period 

reveals a similar pattern. Table 1 and Table 2 below report the total number of trades, the 

total share volume and total dollar volume for trades executed between 2:40 p.m. and 

3:00 p.m., for losses and gains, respectively. The losses/gains are computed as the 

difference between the trade price and the 2:40 p.m. price, divided by the 2:40 p.m. price, 

for each stock. The data do not include out-of-sequence trades.10 Table 1 indicates that 

most investors that sold during this period transacted at prices that were within -10% 

away from the 2:40 p.m. price. Approximately 4.9 million, or 98%, of the trades that 

were executed during this period at prices less than the 2:40 p.m. price were within -10% 

of the 2:40 p.m. price. Approximately 102,000 trades were executed during the decline 

and recovery at prices that were -10% or more away from the 2:40 p.m. price; these 

trades are discussed in section IV.A.2 below. We see a similar pattern in Dow stocks. 

Four out of 30 (about 13%) had returns that were less (more negative) than -10%. Table 

3 indicates the lowest trade price executed for each of the Dow Jones Industrial Average 

component stocks and the return computed against the stock’s 2:40 p.m. trade price. Of 

these stocks, four, Proctor& Gamble (PG), 3M (MMM), Hewlett-Packard (HPQ), and 

General Electric (GE), traded at a loss of over 10%, relative to the 2:40 p.m. price. 

                                                       

10 An “out-of-sequence” trade occurs when the TAQ data identifies the posted trade time as 

incorrect. In this case, the actual time at which the trade was placed is unknown. 
 

20

Table 1: Trades Executed at a Loss

Total # 

trades 

Total volume Total volume ($) 

All trades 7,135,104 1,995,000,637 56,651,582,692 

Losses 5,013,724 1,358,709,226 38,047,617,508 

 0% to -10% 4,912,125 1,324,448,213 37,383,122,363 

-10% to -20% 63,890 22,171,745 522,444,343 

-20% to 30% 12,923 4,077,881 85,328,519 

-30% to -40% 6,112 2,317,245 30,461,333 

-40% to -50% 2,519 767,393 9,641,261 

-50% to -60% 1,682 472,624 8,334,944 

-60% to -70% 1,056 370,920 4,328,898 

-70% to -80% 798 292,061 2,245,851 

-80% to -90% 1,109 237,259 1,152,480 

-90% to -100% 11,510 3,553,885 557,516 

Table 2: Trades Executed at a Gain

Total # trades Total volume Total volume ($) 

All trades 7,135,104 1,995,000,637 56,651,582,692 

Gains 2,121,380 636,291,411 18,603,965,183 

0% to 10% 2,108,076 632,378,310 18,079,956,948 

10% to 20% 10,075 3,039,456 53,123,704 

20% to 30% 927 281,383 8,589,789 

30% to 40% 517 167,439 1,827,449 

40% to 50% 106 32,866 536,641 

50% to 60% 45 19,188 358,048 

60% to 70% 67 14,466 387,321 

70% to 80% 184 46,456 1,147,215 

80% to 90% 178 44,075 1,143,755 

> 90% 1,205 267,772 456,894,313 
 

21

Table 3: Maximum Trade Loss for Dow 30 Stocks

Company Return Low Price Time 

The Proctor& Gamble Company -36.14% $39.37 2:47:15 PM

3M Company -18.39% $67.98 2:46:06 PM

Hewlett-Packard Company -11.81% $41.94 2:46:13 PM

General Electric Company -10.23% $15.00 2:46:11 PM

Merck & Company Incorporated -9.23% $30.70 2:46:11 PM

Exxon Mobil Corporation -8.74% $58.46 2:46:52 PM

E.I. Du Pont De Nemours -8.13% $33.66 2:46:29 PM

Cisco Systems Incorporated -7.52% $23.23 2:45:33 PM

The Walt Disney Company -7.49% $31.00 2:45:45 PM

United Technologies Corporation -7.42% $65.17 2:46:38 PM

International Business Machines Corporation -7.20% $116.00 2:46:33 PM

Chevron Corporation -7.18% $71.50 2:47:03 PM

Intel Corporation -6.09% $19.90 2:47:30 PM

The Boeing Company -5.89% $62.00 2:45:42 PM

Verizon Communications -5.73% $26.49 2:45:48 PM

Johnson & Johnson -5.70% $60.03 2:46:10 PM

Kraft Foods Incorporated -5.21% $27.49 2:47:59 PM

Home Depot Incorporated -5.06% $32.07 2:45:57 PM

Pfizer Incorporated -4.64% $15.85 2:46:06 PM

Caterpillar Incorporated -4.50% $58.00 2:45:33 PM

American Express Company -4.47% $40.16 2:45:52 PM

Alcoa Incorporated -4.34% $11.25 2:47:35 PM

Microsoft Corporation -4.16% $27.91 2:46:39 PM

AT&T Incorporated -3.88% $24.04 2:46:04 PM

Wal-Mart Stores Incorporated -3.74% $51.53 2:45:29 PM

Bank of America Corporation -3.55% $15.50 2:46:36 PM

The Coca Cola Company -3.47% $51.21 2:47:23 PM

McDonalds Corporation -3.43% $67.49 2:47:53 PM

JP Morgan Chase & Company -2.51% $39.29 2:45:45 PM

The Travelers Companies Incorporated -2.31% $48.53 2:45:46 PM

 Both aspects of the 20-minute phenomenon—the effects on the broad market and 

the even more extreme effects on a minority of securities—warrant serious analysis, 

given the potential harm to investor confidence and the realized losses of investors. 

Although the state of our fact-gathering makes any analysis at this time too preliminary to 

draw firm conclusions—or even many tentative ones—about how and why the events of 

May 6 occurred, the facts we have and the analysis we have completed thus far do offer a 

few clues to the origins of the May 6 event. 
 

22

We are in the process of obtaining and reviewing the order book and the data 

necessary to reconstruct the order audit trail for the various equity exchanges and 

electronic communications networks (“ECNs”) in the hope of being able to determine 

whether order book liquidity substantially thinned immediately prior to 2:40 p.m. For 

example, based on some preliminary data, there may be reason to believe that there may 

have been a thinning of order book liquidity at one significant exchange at around 2:00 

p.m. 

 The temporary nature of the decline in prices in the broader market may be 

indicative of a failure in liquidity. As we will show, many individual securities exhibited 

more extreme temporary price movements than the broad market, consistent with a 

broader set of liquidity failures. The discussion that follows focuses on a key issue on 

May 6 – the interaction between liquidity demand and supply. A temporary price 

dislocation could be caused by an unusually high demand for liquidity, by an unusually 

weak supply of liquidity, or by some combination of these factors. Our preliminary 

analysis indicates that both of these factors may be at play. In this section, we focus on 

questions that bear on this central issue. 

NYSE’s trading system incorporates LRPs that are intended to dampen volatility 

in a given stock by temporarily converting from an automated market to a manual auction 

market when a price movement of a sufficient size is reached. In such case, trading on 

the NYSE will “go slow” and pause for a time period to allow an opportunity for 

additional liquidity to enter the market. During an LRP, the NYSE will display a 

quotation that is not immediately accessible and can be bypassed, but is not required to be 

bypassed, by other trading venues and order routers. 

Figure 9 compares the May 6 LRP profile on the NYSE with the average profile 

of such events during 2010. The figure indicates the number of securities that triggered 

an LRP event lasting more than 1 second during any given 30-minute period. The blue 

blocks, reported first in the series, represent the average number of securities meeting this 

criterion from January 4, 2010 through May 6, 2010. The yellow blocks, reported second 

in the series, represent the LRP events on May 6, 2010 itself. 

Figure 9 shows a substantial increase in the number of securities with LRPs on the 

NYSE starting in the period from 1:00 p.m. to 1:30 p.m. and rising to more than 200 in 

the period from 2:00 p.m. to 2:30 p.m. Between 2:30 and 3:00 pm, the level rose to 

approximately 1,000. This significant rise in LRPs could be indicative of a thinning of 

order book liquidity at the NYSE. 
 

23

Figure 9:  Average Daily Profile of NYSE LRP Events

Average Daily Profile of NYSE LRP Events

Jan 4, 2010 - May 6, 2010

0

200

400

600

800

1000

1200

9:45 10:15 10:45 11:15 11:45 12:15 12:45 13:15 13:45 14:15 14:45 15:15 15:45

Mid-point to Half-hour Intervals

LRP Events Greater than 1 Second

May 6: LRPs increase 

starting 13:30

May 6: Severe Market 

Decline starts ~14:40

May 6: Day Begins with 

Average Profile

Source:  NYSE

 Finally, Figure 10 shows a scatter plot of the time and percentage decline for all 

securities that realized their daily low measured from May 5 close to their May 6 low 

during the period between 2:00 p.m. and 3:00 p.m. Each point on the plot represents one 

stock, the time of day it executed a trade at its lowest trade price of the day, and the 

return from the previous night’s close to that trade price. It shows a steady increase in the 

number of securities with daily lows throughout the hour. 
 

24

Figure 10: Timing of Daily Lows, May 6, 2:00pm to 3:00pm11

-120.00%

-100.00%

-80.00%

-60.00%

-40.00%

-20.00%

0.00%

20.00%

14:00:00

14:05:00

14:10:00

14:15:00

14:20:0014:25:00

14:30:00

14:35:0014:40:00

14:45:0014:50:00

14:55:00

Return (%)

Source:  Thomson Financial Datastream and NYSE Trades and Quote

                                                       

11 Figure 10 depicts the timing of daily lows during the one-hour period from 2:00 p.m. to 3:00 p.m. 

on May 6. Each point represents the return from the May 5 close to the lowest transaction price on 

May 6, plotted against the time at which the transaction occurred. Daily lows not occurring during 

this one-hour interval are not depicted. The figure includes all equity securities (common and 

preferred) of corporate issuers, exchange-traded products, closed-end funds, and ADRs, traded on 

major U.S. exchanges, with a share price of more than $3.00 and a market capitalization of at least 

$10 million as of the May 5 close. 
 

25

Figure 11:  Timing of Daily Highs, May 6, 2:00 p.m. to 3:00 p.m.12

-50.00%

0.00%

50.00%

100.00%

150.00%

200.00%

250.00%

300.00%

14:00:00

14:05:00

14:10:00

14:15:00

14:20:00

14:25:00

14:30:00

14:35:00

14:40:00

14:45:00

14:50:00

14:55:00

Return (%)

Sources:  Thomson Financial Datastream and NYSE Trades and Quote.

 While a large number of securities experienced extreme low trades during the 

2:00 p.m. to 3:00 p.m. interval, a smaller but still significant number of securities 

experienced extreme highs. Figure 11 indicates positive returns on May 6, excluding a 

few stocks for scaling reasons. The figure shows that a significant number of securities 

experienced daily highs more than 25% higher than their close on May 5. These extreme 

highs were concentrated after 2:44 p.m. Unlike the lows depicted in Figure 10, which 

began to occur in the early part of the hour, there appear to be no extreme highs occurring 

prior to 2:44 p.m. 

Another factor potentially relevant to the thinning of liquidity is the declaration of 

self-help by NASDAQ against NYSE Arca at 2:37 p.m., and by NASDAQ OMX BX 

against NYSE Arca at 2:38 p.m. We have not yet evaluated the basis for the exercise of 

                                                       

12 Figure 11 depicts the timing of daily highs during the one-hour period from 2:00 p.m. to 3:00 p.m. 

on May 6. Each point represents the return from the May 5 close to the highest transaction price 

on May 6, plotted against the time at which the transaction occurred. Daily highs not occurring 

during this one-hour interval are not depicted. The figure includes all equity securities (common 

and preferred) of corporate issuers, exchange-traded products, closed-end funds, and ADRs, traded 

on major U.S. exchanges, with a share price of more than $3.00 and a market capitalization of at 

least $10 million as of the May 5 close. For scaling purposes, Figure 11 excludes returns to daily 

highs on a few equity securities of corporate issuers. 
 

26

self-help against NYSE Arca. Under Regulation NMS, exchanges are entitled to exercise 

self-help when another exchange repeatedly fails to provide a response to incoming 

orders within one second. The direct effect of a declaration of self-help is that the 

declaring exchanges will no longer route orders to the affected exchange. We are not 

aware, however, that any broker-dealer or any other exchange declared self-help against 

NYSE Arca prior to the time the broad market indexes reached their daily lows.13 

Consequently, the broker-dealers and other exchanges that wished to access NYSE Arca 

quotes would have been likely to route orders directly to NYSE Arca (and therefore 

would not have been affected by a self-help declaration), rather than trying to access 

those quotes indirectly through NASDAQ or NASDAQ OMX BX. Accordingly, we are 

evaluating the extent to which the declaration of self-help by the two exchanges against 

NYSE Arca prior to 2:40 p.m. could have caused a significant thinning of available 

liquidity. 

 Another interesting question remains as to whether electronic liquidity providers 

pulled back during the relevant timeframe. At approximately 2:40 p.m. on May 6, prices 

declined rapidly across many trading venues and products. The activities of electronic 

liquidity providers are important subjects for analysis. These proprietary trading firms 

have come to be the dominant type of liquidity provider in the U.S. equity markets. 

Consequently, we are analyzing their activities on May 6. As noted above, we are in the 

process of obtaining and reviewing the order book data of exchanges and ECNs. We 

have, in the meantime, obtained other data from the exchanges concerning the activity of 

their top ten liquidity providing firms from 2:00 p.m. to 3:00 p.m. We continue to 

analyze these data to assess the activity of these liquidity providing firms. Some initial 

findings based on these data are set forth in Figure 12 and Figure 13below.14

                                                       

13 Two other exchanges – BATS and NSX – exercised self-help against NYSE Arca after this time. 

14 All of the equity exchanges provided data on their liquidity providers. Each exchange was 

requested to identify and provide data on the top ten overall liquidity providers (“Top Ten 

Providers”) on the exchange on May 6. For each of the Top Ten Providers, the exchange was 

requested to provide (1) the number of trades and share volume of liquidity provided on the 

exchange from 2:00 p.m. to 3:00 p.m., broken down in 30 second intervals, for all securities traded 

on the exchange in the aggregate; and (2) the number of trades and share volume of liquidity 

removed on the exchange from 2:00 p.m. to 3:00 p.m., broken down in 30 second intervals, for all 

securities traded on the exchange in the aggregate. 
 

27

Figure 12: Liquidity Provided/Taken by Top 10 Liquidity Providers Across All Equity Markets

2:00 p.m. ­ 3:00 p.m. May 6, 201015

0

10,000,000

20,000,000

30,000,000

40,000,000

50,000,000

60,000,000

14:00:0014:05:0014:10:0014:15:0014:20:0014:25:0014:30:0014:35:0014:40:0014:45:0014:50:0014:55:0015:00:00

30-Second Period Ending

Volume Provided or Taken

Provided Taken

Source:  All data was provided by the exchanges

                                                       

15 The aggregate number of shares taken and provided by each of the top ten liquidity providers for 

each exchange reported in 30-second intervals. 
 

28

Figure 13: Percent of Liquidity Provided/Taken by Top 10 Liquidity Providers against Total

Volume Across all Equity Markets 2:00 p.m. – 3:00 p.m. May 6, 201016

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

14:00:0014:05:0014:10:0014:15:0014:20:0014:25:0014:30:0014:35:0014:40:0014:45:0014:50:0014:55:0015:00:00

30-Second Period Ending

% Provided or Taken

0

10

20

30

40

50

60

70

80

90

100

Total Volume (MM)

%-Provided %-Taken Total Volume

Sources:  Liquidity data provided by the exchanges; total volume from NYSE Trades and Quotes.

 Figure 12 shows the share volume of aggregate liquidity provided and removed 

for all stocks by the top 10 firms for all of the exchanges between 2:00 p.m. and 2:59 

p.m. Figure 13 shows the percentage of liquidity provided and removed against the total 

volume across all equity markets. Figure 12 and Figure 13 could indicate that, 

collectively, these particular firms appear to have remained net liquidity providers 

throughout this period and that they increased their liquidity provision, both in terms of 

share volume and percentage of total volume, when total volume increased at 

approximately 2:40 p.m. We note, however, that the underlying data provided by the 

exchanges as the source for these figures are also consistent with significant variations in 

the activities of different liquidity providers during this period. In addition, it should be 

noted that Figure 12 and Figure 13 represent only the number and percentage of shares of 

liquidity, and not the prices of the transactions which, of course, are important to a 

complete understanding of liquidity provider behavior. Anecdotal evidence, moreover, 

indicates that at least some large electronic liquidity providers and other liquidity 

providers did withdraw from the market during this time. We continue to analyze the 

conduct of these and other primary liquidity providing firms. 

                                                       

16 The percent provided and taken and provided by each of the top ten liquidity providers for each 

exchange reported in 30-second intervals. 
 

29

2. Securities that Suffered Declines Disproportionate 

to the Broader Market 

 As noted above, the great majority of individual securities traded at prices that 

were consistent with the broader market decline during the day, while approximately 

14% of U.S.-listed securities reached lows for the day that were more than 10% away 

from the 2:40 p.m. price. Table 1 and Figure 8 above show that a similar proportion of 

trades in securities hit lows for the day that were more than 10% from the previous day’s 

close.17 This section discusses the individual securities that suffered declines that are out 

of proportion to the broader market. We first focus on broken trades, including ETFs in 

particular. The actual dollar volume of these broken trades was of course small, due to 

artificially low share prices involved, but the shares involved in those trades would have 

been valued at $212.4 million, at their 2:40 p.m. benchmark price. (See Table 7 below). 

We then address securities that otherwise experienced unusually severe declines without 

reaching the threshold for broken trades. 

a) Securities with Broken Trades

The securities exchanges and FINRA have adopted “clearly erroneous execution 

rules” that are designed to permit them to cancel trades that in their determination were 

clearly entered into in error.18 On May 6, under these rules, the SROs broke trades that 

were effected from 2:40 p.m. to 3:00 p.m. at prices 60%19 away from the last trade at or 

before 2:40 p.m. Table 4 below provides certain information regarding the securities in 

which trades were broken.20

A total of 7,878 securities were traded during this period. Trades were broken in 

326 individual securities, consisting of those that experienced a very severe price move of 

60% or greater from the 2:40 p.m.21 No trades were broken in any of the stocks that 

comprise the DJIA. Trades were broken in only 12 stocks that are included in the S&P 

500 Index and in only 30 stocks included in the smaller capitalization Russell 2000 

                                                       

17 We use 10% as an estimated cutoff for stocks that declined by amounts consistent with the overall 

market decline because, on any given day with a significant decline in prices, some stocks will 

decline less and some will decline more. On May 6, for example, 11 DJIA stocks declined by less 

than 5% from the 2:40 p.m. price, and 26 DJIA stocks declined by less than 10% from the 2:40 

p.m. price. (Table 3) 

18 See description of clearly erroneous rules in Appendix A. 

19 Following the wide-scale disruption of May 6, 2010, the exchanges and FINRA settled on the 

relatively high 60% standard for breaking trades. We understand a substantially lower standard – 

10%-20% – typically is selected for the more common discrete erroneous trade events involving 

one or a few securities. The SEC is working with the exchanges and FINRA to establish more 

transparent and objective standards for breaking erroneous trades. 

20 The term “broken trades” for these purposes means all trades identified as broken trades by the 

exchanges and FINRA for May 6, 2010. 

21 From April 1, 2010 to May 5, 2010, the average number of broken trades (excluding FINRA 

trades) was 118.25. 
 

30

Index. Trades were broken in 227 of the 838 ETFs, however. These ETFs represent 

69.6% of all securities with broken trades. 

Table 4: Distribution of Securities and Securities with Broken Trades

Market Broken

Total % Total % 

Securities 7,878 100.0% 326 100.0%

Primary Listing on NYSE 3,277 41.6% 56 17.2%

Primary Listing on NASDAQ 2,946 37.4% 42 12.9%

Primary Listing on ARCA 1,088 13.8% 225 69.0%

Primary Listing on Amex 567 7.2% 3 0.9%

Component of DJIA 30 0.4% 0 0.0%

Component of S&P 500 500 6.3% 12 3.7%

Component of Russell 2000 2,000 25.4% 30 9.2%

Exchange-Traded Fund 838 10.6% 227 69.6

The distribution of all stocks and stocks that had broken trades on May 6, 2010 by primary listing 

exchange, inclusion in key stock indices and the number of Exchange Traded Funds

Sources:  NYSE, NYSEAmex, NYSE Arca, NASDAQ, BATS, CBOE Stock Exchange, ISE, NASDAQ­BX,

National Stock Exchange, Chicago Stock Exchange and FINRA.

The 99 securities22 with broken trades that are not ETFs include securities of a 

wide variety of issuers, both large and small (including 10 exchange-traded products, or 

ETPs, that are not ETFs) and there may be a variety of explanations for their aberrant 

behavior. We continue to investigate the trading in these securities on May 6 to 

determine whether there is a common cause or causes for the trading anomalies, such as a 

particular susceptibility to liquidity withdrawal or an unusually large number of stop loss 

market orders. 

 Tables 5 and 6 below provide certain information regarding the distribution of 

trades that were broken, both by trading venue and by time period. These tables show 

that 20,761 trades were broken on May 6, with 12,306 (59.3%) broken by NASDAQ, 

4,903 (23.6%) broken by NYSE Arca, 1,816 (8.7%) broken in the OTC market, and 

1,094 (5.3%) broken by BATS. No trades were broken by NYSE. 

Table 5 and Table 6 show the distribution of securities in which broken trades 

occurred by markets.23

                                                       

22 The total of 326 securities with broken trades is comprised of 227 ETFs, 10 ETPs that are not 

ETFs and 89 stocks. 

23 The number of broken ADF/TRF trades counts only trades that were not rejected by ACT and that 

were reported to the tape. 
 

31

Table 5:  Number of Trades Executing on Each Market

2:20-

2:40p.m.

2:40-

3:00p.m.

Number of

Broken 

Trades

Total Trades 5,721,383 7,318,675 20,761

Average Trade Size 286.68 282.03 270.33

 On NYSE 667,368 1,039,233 0 

 On Amex 4,154 6,965 4 

 On ARCA 886,899 1,110,765 4,903 

 On NASDAQ 1,482,761 2,052,647 12,306 

 On BATS 988,252 1,177,318 1,094 

 On CBOE 2,902 4,743 138 

 On ISE 87,313 171,978 403 

 On NASDAQ-BX 271,119 401,549 63 

 On National 35,386 58,085 27 

 On Chicago 5,845 10,748 7 

 On ADF/TRF 1,287,489 1,101,252 1,816 

Sources:  NYSE, NSYEAmex, NYSEARCA, NASDAQ, BATS, CBOE Stock Exchange, ISE, NASDAQ­BX,

National Stock Exchange, Chicago Stock Exchange and FINRA
 

32

Table 6:  Percentage of Trades Executing on Each Market

2:20-

2:40p.m.

2:40-

3:00p.m.

Percentage 

of Broken 

Trades

Total Trades 5,721,383 7,318,675 20,761

Average Trade Size 286.68 282.03 270.33

 On NYSE 11.70% 14.60% 0.00% 

 On Amex 0.10% 0.10% 0.00% 

 On ARCA 15.50% 15.60% 23.60% 

 On NASDAQ 25.90% 28.80% 59.30% 

 On BATS 17.30% 16.50% 5.30% 

 On CBOE 0.10% 0.10% 0.70% 

 On ISE 1.50% 2.40% 1.90% 

 On NASDAQ-BX 4.70% 5.60% 0.30% 

 On National 0.60% 0.80% 0.10% 

 On Chicago 0.10% 0.20% 0.00% 

 On ADF/TRF 22.50% 15.40% 8.70% 

Sources:  NYSE, NSYEAmex, NYSEARCA, NASDAQ, BATS, CBOE Stock Exchange, ISE, NASDAQ­BX,

National Stock Exchange, Chicago Stock Exchange and FINRA

We continue to analyze the distribution of broken trades across markets to 

determine whether differences in market structure may have had an impact. Because 

NYSE pauses or slows trading in volatile periods when a LRP is triggered, this likely 

explains why NYSE had no broken trades on May 6. Some have suggested that LRPs 

exacerbated price volatility on May 6 by causing a net loss of liquidity as orders were 

routed to other trading venues for immediate execution rather than wait on the LRP 

mechanism. If accurate, this potentially could cause some NYSE securities to decline 

further than the broad market decline. Others believe that the LRP mechanism served to 

attract additional liquidity that helped soak up some the excess selling interest in these 

securities on May 6. In any event, nearly 83% of the securities with broken trades do not 

trade on NYSE, as NYSE trades only NYSE-listed stocks, and thus could not have been 

directly affected by NYSE LRPs. A determination of the extent to which the use of LRPs 

by NYSE contributed to the volatility on May 6 requires further study. 

Also worth noting is the relatively low number of broken trades on BATS, 

relative to its share of trading volume. Although more study is required, one explanation 

for this could be that BATS does not refresh “stub quotes.” The SEC staff is reviewing 

the extent to which the use of stub quotes contributed to the volatility on May 6, and is 

considering possible policy responses. 
 

33

Table 7:  Broken Trades by Time Period ­ May 6, 2010

Description Before 

2:40 

2:40 -

2:45 

2:45 - 

2:50 

2:50 - 

2:55 

2:55 - 

3:00 

After 

3:00 

Total 

Panel A: All Broken Trades 

# of Broken Trades 209 91 11,446 4,703 2,011 2,301 20,761 

> 14:40 price 20 1 156 1,130 95 2,158 3,560 

< 14:40 price 189 90 11,290 3,573 1,914 143 17,201 

> 160% of 14:40 price 13 0 156 1,130 93 1,011 2,403 

< 40% of 14:40 price 186 90 11,290 3,572 1,914 143 17,195 

< 5¢ 148 6 5,158 1,928 175 1 7,416 

Share Volume (x000) 37 57 3,165 1,136 636 582 5,612 

$ Volume (by 14:40 pm price in 

$MM) 

1.3 2.1 132.4 29.3 17.6 29.7 212.4 

Return from 14:40 price 

(weighted) 

245% -97% -93% -41% 119% 2976% 262% 

Panel B: Broken Trades that are Short Sales 

% of Broken Trades 16.3% 4.4% 42.0% 52.6% 12.1% 54.2% 42.4% 

> 14:40 price 20.0% 0.0% 4.5% 45.1% 2.1% 57.7% 49.7% 

< 14:40 price 15.9% 4.4% 42.5% 55.0% 12.6% 1.4% 40.9% 

> 160% of 14:40 price 15.4% 0.0% 4.5% 45.1% 2.2% 50.0% 42.7% 

< 40% of 14:40 price 16.1% 4.4% 42.4% 54.7% 12.6% 1.4% 40.8% 

< 5¢ 20.3% 0.0% 70.9% 90.1% 39.4% 0.0% 74.0% 

Share Volume (% of Broken 

Trades) 

9.8% 3.0% 19.0% 36.7% 12.2% 50.4% 24.9% 

$ Volume (% of Broken Trades) 6.0% 1.8% 14.5% 30.3% 9.5% 54.8% 21.7% 

Return from 14:40 price 

(weighted) 

-76% -97% -92% -21% -95% 81% -35% 

Source:  All trade data from SROs.  Price data from NYSE Trades and Quotes.

Table 7 shows that, during the core 2:40 p.m. to 3:00 p.m. period, broken trades 

peaked between 2:45 p.m. and 2:55 p.m., with 11,446 broken trades executed from 2:45 

p.m. to 2:50 p.m. and 4,703 broken trades executed between 2:50 p.m. and 2:55 p.m. As 

expected, this corresponds with the period of peak volatility and trading volume in the 

securities markets. 

Table 7also shows the number of trades that occurred at extraordinarily low prices 

– five cents or less – which indicates an execution against a “stub” quote of a market 

maker. A total of 7,416 of these trades took place during the core 2:40 p.m. to 3:00 p.m. 

period, with the highest levels occurring, as expected, between 2:45 p.m. and 2:50 p.m. 

(5,158) and 2:50 p.m. and 2:55 p.m. (1,928). 

Table 7 further shows the number of broken trades identified as short sales. 

During the period of peak market volatility, 2:45 p.m. to 2:55 p.m., the broken trades 

executed at five cents or less were primarily short sales. Short sales account for 

approximately 70.1% of executions against “stub” quotes between 2:45 p.m. and 2:50 

p.m., and approximately 90.1% of executions against “stub” quotes between 2:50 p.m. 
 

34

and 2:55 p.m. It is worth noting that short sale executions against stub quotes at or below 

the prevailing national best bid would be subject to the alternative uptick rule (Rule 201) 

adopted by the SEC on February 24, 2010, with a compliance date of November 10, 

2010.24 The SEC staff is continuing to review short selling activity on May 6, including 

the apparent high level of short selling against “stub” quotes during the period of peak 

market volatility. 

Figure 8 shows that these stub quote executions occurred in more than 200 

securities, across large, medium and small capitalization stocks, but with a concentration 

in small capitalization securities. Although more study is required, the higher level of 

stub quote executions in smaller capitalization securities is consistent with their tendency 

to have less liquidity, and thus a greater likelihood that selling interest could overwhelm 

order books in times of heightened volatility. As noted above, the SEC is reviewing the 

extent to which the use of stub quotes contributed to the volatility on May 6, and is 

considering possible policy responses. 

One example of a security where there were executions against stub quotes is 

Accenture (ACN). The data set forth below indicates that share prices of Accenture fell 

from nearly $40 to a penny and recovered all of their value within a matter of seconds. 

We are investigating this dramatic spike to determine possible causes and explanations, 

including its relation to the broader market disruption. 

                                                       

24 Under Rule 201, trading centers will be required to have and enforce policies and procedures 

reasonably designed to prevent executions of short sales at or below the national best bid once the 

stock price has experienced a ten percent decline relative to the prior day’s closing price. 
 

35

Figure 14:  Price Chart for Accenture plc (Ticker = ACN)25

$0.00

$5.00

$10.00

$15.00

$20.00

$25.00

$30.00

$35.00

$40.00

$45.00

14:47:3714:47:3814:47:3914:47:4014:47:4114:47:4214:47:4314:47:4414:47:4514:47:4614:47:4714:47:4814:47:4914:47:5014:47:5114:47:5214:47:5314:47:5414:47:5514:47:5614:47:5714:47:5814:47:5914:48:0214:48:0314:48:0414:48:0514:48:17

0

4

8

12

16

20

Thousands

Price Best Offer Best Bid Volume

Lowest 

price

$0.01 from 

14:47:54 to 

14:48:01

Source:  All data from NYSE Trades and Quotes

The figure above shows that bids for Accenture plc (ACN) rapidly declined in 7 

seconds from about $30 at 2:47:47 p.m., to $0.01 by 2:47:54 p.m.. The black bars show 

that trades were being made at both the stub quote of $0.01 and the ask price of over $30 

within the same second. 

ETFs: As previously discussed, the data suggests that ETFs as a class were 

affected more than any other category of securities. Trades in securities issued by ETFs 

appear to have accounted for nearly 70% of the securities in which trades were broken on 

May 6. Figure 15 shows the distribution of ETF daily lows during May 6. A relatively 

large number of ETFs, approximately 160, experienced lows during the day 

approximately 100% lower than the May 5 close, represented by the spike on the left-

                                                       

25 This chart and the others below depicting single security price charts plot the second-by-second 

activity of trades, quotes, and volume for the security indicated. Each thick vertical bar (in black) 

shows the high/low range of all prices executed for all trades within a given second (scale on left 

axis). The red line shows the lowest National Best Bid quoted across all exchanges during that 

second. The green line shows the highest National Best Offer quoted across all exchanges during 

that second. The thick blue vertical lines indicate the total volume of shares traded each second 

(scale on right axis). 
 

36

hand side of the figure. A significant number of ETFs also experienced less extreme, but 

still notable lows of between 35% and 100% relative to their corresponding May 5 close. 

A larger cluster of ETFs experienced lows approximately 8% below May 5 close. 

This clustering of daily lows around -8% is consistent with the daily low in the broader 

market, which was approximately 8.5% for the S&P 500. However, relative to the 

distribution of losses of all securities, (depicted above in Figure 8), extreme daily lows 

appear to have been more common in the ETFs (as depicted in Figure 15). Figure 15 

does not reveal an obvious relation between ETF market capitalization and daily lows. 

Tables 8 and 9 report the total number of trades, the total volume and total dollar 

volume for ETF trades executed between 2:40 p.m. and 3:00 p.m., for losses and gains, 

respectively. The tables are based on 838 registered ETFs as derived from Morningstar. 

The losses/gains are computed as the difference between the trade price and the 2:40 p.m. 

price, divided by the 2:40 p.m. price, for each stock. The data do not include out-ofsequence trades. 

Table 8:  Trades Executed at a Loss

Total # 

trades 

Total volume Total volume ($) 

All trades 1,265,637 456,335,890 22,381,572,444 

Losses 794,607 279,836,213 14,135,649,267 

 0% to -10%     761,866   269,307,656   13,909,304,917 

-10% to -20%       13,607       3,988,959        145,247,171 

-20% to 30%        3,714       1,144,431          40,234,001 

-30% to -40%        2,041         753,856          18,934,582 

-40% to -50%        1,151         320,661           6,612,612 

-50% to -60%        1,148         344,774           7,657,548 

-60% to -70%           758         314,030           4,111,592 

-70% to -80%           505         233,617           2,021,741 

-80% to -90%           775         176,632           1,025,499 

-90% to -100%        9,042       3,251,597              499,604 

Source:  NYSE’s Trades and Quotes
 

37

Table 9:  Trades Executed at a Gain

Total # 

trades 

Total volume Total volume ($) 

All trades 1,265,637 456,335,890 22,381,572,444 

Gains 471,030 176,499,677 8,245,923,177 

0% to 10% 468,197 175,697,855 8,221,468,066 

10% to 20% 2,392 712,398 18,350,149 

20% to 30% 99 30,162 1,330,565 

30% to 40% 28 6,668 240,300 

40% to 50% 35 4,300 184,047 

50% to 60% 12 1,600 77,897 

60% to 70% 19 5,996 266,038 

70% to 80% 30 5,166 511,016 

80% to 90% 41 4,500 450,227 

> 90% 177 31,032 3,044,872 

Source:  NYSE Trades and Quotes

Table 8 indicates that, out of the 280 million ETF shares that traded below the 

2:40 p.m. price, approximately 269 million, or 96%, traded at prices above or within 10% 

of the 2:40 p.m. price. A significant number of shares, approximately 3 million, traded at 

90-100% losses. Dollar volume for trades at 90-100% losses is low, at $499,600, but 

purely as a mechanical consequence of low share prices. Significantly fewer shares of 

ETFs traded at large gains than traded at large losses. Table 9 indicates that only 712,398 

shares traded at gains of 10% to 20%. In the aggregate, approximately 800,000 shares, 

with a dollar volume of $24.5 million, traded at a more than 10% gain. 

Figure 15 indicates the distribution of ETF daily lows during May 6. A relatively 

large number of ETFs, approximately 160, experienced lows during the day 

approximately 100% lower than the May 5 close, represented by the spike on the lefthand side of the figure, and a number of ETFs also experienced less extreme, but still 

notable, lows between, 35% and 100% below the May 5 close. A larger cluster of ETFs 

experienced lows approximately 7% below the May 5 close, a concentration that may be 

a byproduct of the temporary dislocation in the broad market. In some ETFs, daily lows 

were approximately the same as the May 5 close, represented by the modest spike on the 

right-hand side of the chart. Relative to the distribution of all securities, depicted above 

in Figure 8, extreme daily lows appear to have been more common in the ETFs. 
 

38

Figure 15:  Distribution of May 6 Daily Lows for ETFs26

0

20

40

60

80

100

120

140

160

180

-100%

-95%

-90%

-85%

-80%

-75%

-70%

-65%

-60%-55%

-50%

-45%

-40%

-35%

-30%

-25%

-20%

-15%

-10%

-5%

0%

Return from May 5 Close to May 6 Low

Number of Issues

Market Cap over $5 Billion

Market Cap between $500 Million and $5 Billion

Market Cap between $10 and $500 Million

Sources:  Thomson Financial Datastream and NYSE Trades and Quotes.

                                                       

26 Figure 15 depicts the distribution of returns from close on May 5 to the lowest transaction price on 

May 6. The securities included are ETFs trading on major U.S. exchanges, with a share price of 

more than $3.00 and a market capitalization of at least $10 million as of the May 5 close. 
 

39

Figure 16: Timing of ETF Daily Lows, May 6, 2:00pm to 3:00 pm27

-120.00%

-100.00%

-80.00%

-60.00%

-40.00%

-20.00%

0.00%

20.00%

14:00:00

14:05:00

14:10:00

14:15:00

14:20:00

14:25:00

14:30:00

14:35:00

14:40:00

14:45:00

14:50:00

14:55:00

Return (%)

Sources: Thomson Financial Datastream and NYSE Trades and Quotes

Over the one-hour interval between 2:00 p.m. and 3:00 p.m., as shown in Figure 

16, many of the daily lows in ETFs occurred after 2:45 p.m. A few ETFs began 

experiencing relatively modest daily lows of approximately 10% below the May 5 close 

shortly after 2:10p.m. These lows continued sporadically until around 2:40p.m., when 

their frequency increased, represented on the graph by the concentration of points on the 

lower right. Many of these daily lows, beginning near 2:45p.m., were approximately 

100% below the May 5 close, represented by the dense line near -100% on the right-hand 

side of the graph. Comparing this figure with Figure 10, which presents the same 

analysis for all securities, ETFs appear relatively less likely than other securities to have 

experienced extreme daily lows during the early part of the hour. 

While many ETFs experienced extreme daily lows during the day, as evidenced 

by the daily lows presented in Figure 16, a significant number of ETFs experienced 

                                                       

27 Figure 16 depicts the timing of ETF daily lows during the one-hour period from 2:00 p.m. to 3:00 

p.m. on May 6. Each point represents the return from the May 5 close to the lowest transaction 

price on May 6, plotted against the time at which the transaction occurred. Daily lows not 

occurring during this one-hour interval are not depicted. The figure includes ETFs trading on 

major U.S. exchanges with a share price of more than $3.00 and a market capitalization of at least 

$10 million as of the May 5 close. 
 

40

extreme daily highs. Figure 17 presents these daily highs, plotted against the time at 

which they occurred. One ETF experienced a daily high approximately 275% higher 

than the May 5 close. Consistent with the pattern for extreme daily lows, the extreme 

daily highs appear to begin near 2:45 p.m. and are notably absent from the early part of 

the hour. 

Figure 17: Timing of ETF Daily Highs, May 6, 2:00 p.m. to 3:00 p.m.28

-50.00%

0.00%

50.00%

100.00%

150.00%

200.00%

250.00%

300.00%

14:00:00

14:05:00

14:10:0014:15:00

14:20:00

14:25:00

14:30:0014:35:00

14:40:00

14:45:00

14:50:00

14:55:00

Return (%)

Sources: Thomson Financial Datastream and NYSE Trades and Quotes

 Figure 18 depicts the number of broken-trade ETFs and the total number of ETFs, 

broken out by asset category. This behavior is very similar to that previously depicted for 

individual companies. 

                                                       

28 Figure 17 depicts the timing of ETF daily highs during the one-hour period from 2:00 p.m. to 3:00 

p.m. on May 6. Each point represents the return from the May 5 close to the highest transaction 

price on May 6, plotted against the time at which the transaction occurred. Daily highs not 

occurring during this one-hour interval are not depicted. The Figure includes ETFs trading on 

major U.S. exchanges with a share price of more than $3.00 and a market capitalization of at least 

$10 million. 
 

41

Figure 18:  Broken­Trade ETFs and ETF Universe

Broken ETFs and ETF Universe

0

10

20

30

40

50

60

70

80

90

Large Value

Large Blend

Bear Market

Large Growth

Equity Energy

Foreign: Lg. Med, Sm

Health

Technology

Financial

Small Blend, Growth

Mid-Cap Blend

Mid-Cap Growth

Mid-Cap Value

Asia, Europe, Lat. Am.

Consumer Discretionary

Consumer Staples

Industrials

Small Value

Utilities

Communications

Natural Res

Diversified Emerging Mkts

Long-Short

Real Estate

Intermediate Government

World Bond

Convertibles

# ETFs Broken

Total ETFs

Source:  NYSE, NYSEAmex, NYSE Arca, NASDAQ, BATS, CBOE Stock Exchange, ISE, NASDAQ­BX, NSX,

Chicago Stock Exchange and FINRA

Tables10, 11 and Figure 18 present summary statistics on broken trades by fund 

company, by net assets, and by asset class. Figure 18 illustrates the relation between fund 

investment objective and the existence of broken trades. It depicts the distribution of 

total ETFs and ETFs with broken trades by asset category. The broken trades are skewed 

toward large- and mid-cap equity ETFs, with fewer broken trades occurring in bond, realestate and ETFs with objectives that do not track the overall market. 

Table 10 classifies broken-trade exchange-traded funds by fund family. All but 

ten of the exchange-traded products with subsequently broken trades were also ETFs, and 

five of those ten appear to be stock-related ETPs. Table 10 indicates that, on average, 

27.1% of all fund companies experienced broken trades. There is, however, considerable 

cross-sectional variation among fund families. For example, First Trust experienced 

broken trades in approximately 50% of its ETFs, while PIMCO had no ETFs with broken 

trades.29

One explanation for this variation may be the degree to which families specialize 

in asset classes that had fewer breaks, such as debt-oriented fund families like PIMCO. It 

is clear that the breaks occurred in many trades of ETFs in fund families (16 of 26 fund 

                                                       

29 Additionally, one fund family appears to account for all five of the commodity-index-related nonETF ETPs that experienced broken trades 
 

42

families) and that, conditional on a break occurring within a particular fund family, not 

all of the ETFs were affected. 

Table 11 examines the relation between ETF size and broken trades by net asset 

quartile. The data suggests that the proportion of broken trades in the smallest net asset 

quartile of ETFs is lower than the others (16.3% versus 30.7%).30 Table 11 also indicates 

that while there are differences across quartiles, the relative volume of broken trades to 

non-broken trades within each quartile did not change very much between May 5 and 

May 6. For example, the May 5 ratio of daily volume of funds that had broken trades on 

May 6 to those without broken trades was 63.8% (46,115/(46,115+26,138)). The 

analogous ratio computed using May 6 volume levels is very similar at 61.7% 

(28,034/(28,034+17,385)). 

                                                       

30 The rate of broken trades for Average Current Net Asset Quartile 1 of 16.3% is computed as 

34/(34+175). An analogous calculation is used to compute the average across the other three 

quartiles. 
 

43

Table 10:  Fund Companies31

ETF Firm Name Broken Not Broken Total 

ALPS ETF 0 6 6 

AdvisorShares 0 1 1 

Claymore Securities 9 25 34 

Direxion Funds 3 31 34 

Emerging Global 0 6 6 

FaithShares 1 4 5 

Fidelity Investments 1 0 1 

First Trust 21 22 43 

Global X Funds 0 10 10 

Grail Advisors 0 7 7 

IndexIQ 2 6 8 

JETS 0 2 2 

OOK Advisors 0 2 2 

Old Mutual 0 4 4 

PIMCO 0 10 10 

PowerShares 43 73 116 

ProShares 22 77 99 

Rydex/SGI 17 14 31 

Schwab Funds 5 3 8 

State Street Global 14 76 90 

VTL Associates, LLC 2 4 6 

Van Eck 2 23 25 

Vanguard 15 31 46 

WisdomTree 9 33 42 

XShares 0 5 5 

iShares 61 136 197 

Total 227 611 838 

Percent of Total 27.1 72.9 100.0 

Source:  NYSE, NYSEAmex, NASDAQ, BATS, CBOE Stock Exchange, ISE, NASDAQ­BX, NSX, Chicago Stock

Exchange and FINRA

                                                       

31 Table 10 presents the number of ETPs with broken trades on May 6, 2010 by fund family 

(sponsor). 
 

44

Table 11:  ETFs with Broken Trades32

Quartile 

Average 

Current 

Net Assets33

Number 

of ETFs 

Average 

Daily 

Volume 

May 6 

Average 

Daily 

Volume 

May 5 

Average Current Net 

Asset 

Broken 1 34 46,115 28,034 $8,321,632

Not Broken 1 175 26,138 17,385 $7,690,493

Broken 2 60 150,390 76,880 $42,167,498

Not Broken 2 150 99,232 60,952 $37,411,891

Broken 3 76 265,000 192,501 $188,958,576

Not Broken 3 133 1,316,488 856,819 $177,878,106

Broken 4 57 5,962,890 3,355,924 $2,586,658,099

Not Broken 4 153 20,746,803 11,972,562 $3,463,601,150

Sources:  Morningstar is the source of current net asset data and Datastream is the source of the

average daily volume data

 The next three charts show the experience of broken trades in three different 

ETFs. 

                                                       

32 This presents the number of ETFs by quartile of average current net assets, with broken trades on 

May 6, 2010 out of all ETFs, the average daily volume for ETFs for May 5, 2010 and May 6, 

2010, and the average net assets of registered ETFs. 

33 ETFs in quartile 1 have current net assets less than $16,312,382. Quartile 2 has ETFs with current 

net assets between $16,312,382 and $75,170,606. Quartile 3 has ETFs with current net assets 

between $75,170,606 and $351,622,059. Quartile 4 consists of ETFs with current net assets 

greater than $351,622,059.
 

45

Figure 19: Price Chart for iShares MSCI EAFE Growth Index Fund (Ticker = EFG)

$0.00

$10.00

$20.00

$30.00

$40.00

$50.00

$60.00

14:45:0014:46:0014:47:0014:48:0014:49:0014:50:0014:51:0014:52:0014:53:0014:54:0014:55:0014:56:0014:57:0014:58:0014:59:00

0

1

2

3

4

5

6

Thousands

Price Best Offer Best Bid Volume

Lowest 

price

$0.0001 at 

14:58:14

Source:  NYSE Trades and Quotes

Figure 19 shows that iShares MSCI EAFE Growth Index Fund (EFG) was thinly 

traded but within a relatively narrow bid-ask spread. However, a number of trades are 

executed below the lowest national best bid, and at 2:58:14 p.m. transactions are executed 

at prices of less than $0.01. 
 

46

Figure 20: Price Chart for iShares Russell 1000 Growth Index Fund (Ticker = IWF)

$0.00

$5.00

$10.00

$15.00

$20.00

$25.00

$30.00

$35.00

$40.00

$45.00

$50.00

14:44:0014:45:0014:46:0014:47:0014:48:0014:49:0014:50:0014:51:0014:52:0014:53:0014:54:0014:55:0014:56:0014:57:0014:58:0014:59:00

0

10

20

30

40

50

60

70

80

90

100

Thousands

Price Best Offer Best Bid Volume

Lowest 

price

$0.0001 at

14:47:28

Source:  NYSE Trades and Quotes

In Figure 20, bids for iShares Russell 1000 Growth Index Fund (IWF) rapidly 

declined just before 2:46 p.m. A number of trades were executed at stub-quotes of less 

than $0.01 and at the highest offer-quote of $20.00 within a 3-minute period, which was 

followed by a two-minute period with almost no trade activity. IWF then slowly 

recovered with widely varying bid and offer quotes. By 2:56 p.m. the bid-ask spread 

narrows and the price increased to approximately 90% of its decline. 
 

47

Figure 21: Price Chart for Vanguard Total Stock Market Fund (Ticker = VTI)

$0.00

$10.00

$20.00

$30.00

$40.00

$50.00

$60.00

14:44:0014:45:0014:46:0014:47:0014:48:0014:49:0014:50:0014:51:0014:52:0014:53:0014:54:0014:55:0014:56:0014:57:0014:58:0014:59:00

0

15

30

45

60

75

90

Thousands

Price Best Offer Best Bid Volume

Lowest 

price 

$0.15 at 

14:55:32

Source:  NYSE Trades and Quotes

Figure 21 indicates that Vanguard Total Stock Market Fund (VTI) maintained 

relatively narrow bid-ask spreads while following the broad market through decline and 

recovery beginning 2:44 p.m. Just prior to 2:55 p.m., bids suddenly collapsed on 

increased volume well after the recovery is underway. And at 2:55:32 p.m. bids drop to 

stub quotes and trades are executed at $0.15 before the price resumes its recovery. 
 

48

For reference, the tables below rank the top 10 ETFs with broken trade and stocks 

(by volume, both for the full day and between 2:00 p.m. and 3:00 p.m. on May 6). 

Table 12:  Top 10 ETFs with Broken Trades by Trading Volume – Full Day, May 6

ETF Ticker Volume 

iShares Russell 2000 Index IWM 195,387,906 

ProShares UltraShort QQQ QID 53,291,398 

iShares Russell 1000 Growth Index IWF 9,002,900 

ProShares Ultra Real Estate URE 6,983,600 

iShares Russell 2000 Value Index IWN 6,823,200 

iShares Russell 1000 Value Index IWD 6,258,200 

Vanguard Total Stock Market ETF VTI 6,160,500 

iShares S&P MidCap 400 Index IJH 5,416,800 

iShares Russell 1000 Index IWB 5,194,400 

Rydex S&P Equal Weight RSP 4,511,600 

Sources:  NYSE, NSYEAmex, NYSEARCA, NASDAQ, BATS, CBOE Stock Exchange, ISE, NASDAQ­BX,

National Stock Exchange, Chicago Stock Exchange and FINRA.

Table 13:  Top 10 ETFs with Broken Trades by Trading Volume – May 6 from 2 p.m. to 3 p.m.

ETF Ticker Volume 

iShares Russell 2000 Index IWM 58,392,711 

ProShares UltraShort QQQ QID 21,771,521 

iShares Russell 1000 Growth Index IWF 3,161,501 

iShares Russell 2000 Value Index IWN 2,671,281 

Vanguard Total Stock Market ETF VTI 2,472,422 

Rydex S&P Equal Weight RSP 2,305,135 

ProShares Ultra Real Estate URE 2,193,949 

iShares Russell 1000 Value Index IWD 1,707,294 

iShares Russell 1000 Index IWB 1,677,658 

iShares S&P MidCap 400 Index IJH 1,407,322 

Sources:  NYSE, NSYEAmex, NYSEARCA, NASDAQ, BATS, CBOE Stock Exchange, ISE, NASDAQ­BX,

National Stock Exchange, Chicago Stock Exchange and FINRA.
 

49

Table 14:  Top 10 Broken Stocks by Trading Volume – Full Day May 6

Stock Ticker Volume 

Radian Group RDN 70,612,297 

Apple Inc. AAPL 45,923,602 

Philip Morris International PM 16,460,300 

Exelon Corp EXC 12,426,400 

Amylin Pharmaceuticals AMLN 11,626,099 

Costco Warehouse COST 11,175,900 

International Group of Companies IPG 11,073,400 

Accenture, PLC ACN 10,311,600 

Amazon AMZN 10,195,600 

CenterPoint Energy CNP 9,322,800 

Sources:  NYSE, NSYEAmex, NYSEARCA, NASDAQ, BATS, CBOE Stock Exchange, ISE, NASDAQ­BX,

National Stock Exchange, Chicago Stock Exchange and FINRA.

Table 15:  Top 10 Broken Stocks by Trading Volume – May 6 from 2 p.m. to 3 p.m.

Stock Ticker Volume 

Apple Inc. AAPL 7,506,380 

Radian Group RDN 5,298,708 

Philip Morris International PM 4,140,829 

International Group of Companies IPG 3,235,083 

Provident Energy Trust PVX 2,622,676 

Exelon Corp EXC 2,509,121 

CenturyTel, Inc CTL 2,248,034 

Accenture, PLC ACN 2,059,138 

Center Point Energy CNP 2,018,251 

Southwestern Energy Company SWN 1,618,107 

Sources:  NYSE, NSYEAmex, NYSEARCA, NASDAQ, BATS, CBOE Stock Exchange, ISE, NASDAQ­BX,

National Stock Exchange, Chicago Stock Exchange and FINRA.

 SEC staff also evaluated whether creation and redemption behavior by authorized 

participants was significantly different on May 5, 6 and 7 between ETFs with broken 

trades and ETFs without broken trades. The staff was provided creation and redemption 

data by four ETF advisors. The data contained daily creation and redemption units or 

shares for all ETFs advised by those firms from approximately April 1 to May 11. Two 

ETF advisors provided their information in number of shares, while two provided theirs 

in number of units. Since shares and units are not directly comparable, the two data sets 

were combined separately in order to run the analysis. Statistical tests were run to 

determine whether the amount of net creations (creations minus redemptions) differed 

between ETFs that experienced broken trades and those that did not. The tests were run 

on creation and redemption data separately for May 5, May 6, and May 7. 
 

50

The results of the tests do not provide evidence that there was a significant 

difference in the creation and redemption behavior of authorized participants between 

ETFs with broken trades and ETFs without broken trades. There are some statistically 

significant results indicating that ETFs with broken trades had higher creations on May 7 

than ETFs without broken trades, although the level of significance is weak. As a 

robustness check, the same tests were run on all days not including May 5, May 6 and 

May 7. The results showed that there is no statistical difference in creation and 

redemption behavior of authorized participants between ETFs with broken trades and 

ETFs without broken trades during the trading window not including May 5, May 6 or 

May 7. It is noted that the tests were completed with very small sample size, limiting 

their power. 

The SEC staff continues to investigate precisely why ETFs as a class were 

affected so dramatically. ETFs are primarily highly transparent pools of securities that 

seek to track market indices. Thus, unlike other listed securities, the value of an ETF is 

dependent on the value of the individual securities it owns as well as the transactions in 

ETF shares by market participants. ETFs are often used by investors and other market 

participants as an efficient means of gaining (or reducing) exposure to market segments 

in connection with their implementation of investment or hedging strategies. 

 As discussed in Appendix A, ETF shares have typically traded at market prices 

that are closely related to the net asset value of their shares. This pricing discipline 

principally hinges on the ability of market makers: (a) to effectively hedge their market 

exposure to ETF shares; and (b) to engage in arbitrage transactions with the ETFs if the 

market prices of the ETF shares deviate significantly from their net asset values. 

 As noted above, certain non-ETF securities experienced extreme daily lows 

earlier than certain ETFs during the one hour interval from 2:00 p.m. to 3:00 p.m. We are 

currently gathering and reviewing data to ascertain the causes of these collapses and the 

possible implications for the broader market. 

 We are also studying the extent to which the use of ETFs may have contributed to 

the abrupt price declines. For example, institutional investors often utilize index-based 

ETFs in hedging strategies, which may have prompted unusual liquidity demands during 

this period of market turmoil. The use of stop loss orders by other investors may have 

created additional sell pressure on ETF shares in a rapidly declining market. 

In addition, we are exploring the impact of “self-help” being invoked by 

NASDAQ and BATS against NYSE Arca. As NYSE Arca is the primary listing 

exchange for almost all ETFs, the loss of access to NYSE Arca’s liquidity pool may have 

had a disproportionate impact on market liquidity and trading for ETFs. 

b) Market Activity in Other Selected Securities

 Significant numbers of securities experienced declines in excess of the broad 

market (meaning, for these purposes, declines of more than 10% from their prices at 2:40 
 

51

p.m.), but did not cross the 60% broken trade threshold. In addition, a significant number 

of securities experienced extreme daily highs after approximately 2:44 p.m.34 In this 

section, we provide examples of specific selected securities to illustrate how 

representative securities behaved during the critical minutes of May 6. 

 For example, some large capitalization securities declined quite substantially. 

One was Proctor & Gamble (PG), whose price chart for May 6 is set forth in Figure 22. 

Figure 22: Price Chart for The Proctor & Gamble Company (Ticker = PG)

$30.00

$35.00

$40.00

$45.00

$50.00

$55.00

$60.00

14:46:3014:46:4514:47:0014:47:1514:47:3014:47:4514:48:0014:48:1514:48:30

0

20

40

60

80

100

120

Thousands

Price Best Offer Best Bid Volume

Lowest price $39.37 

14:47:15 to 14:47:19

Sources: NYSE Trades and Quotes

It can be seen that bids for PG decline rapidly over a one-minute period before 

rapidly ascending and then recovering. Trades occur in a wide range from the lowest 

national best bid in a given second to the highest national best offer in that same second. 

 PG declined from more than $60 to a low of $39.37 in approximately 3.5 minutes 

(a 36.14% decline from the 2:40 p.m. price), then recovered above $60 in approximately 

one minute. Notably, the decline in PG did not begin until 2:44 p.m., well after the 

                                                       

34 In contrast to the stocks that suffered on the downside, the stock of Sotheby’s (BID) is notable for 

displaying aberrant behavior on the upside on May 6 (see Figure 25 and Figure 26). 
 

52

broader market indices, which began their precipitous drop at approximately 2:40 p.m. 

Accordingly, early reports that an inordinately large trade in PG may have triggered the 

broad market decline do not appear well founded. Our analysis of the order book data 

should help shed light on why PG declined and recovered so much more significantly 

than other large capitalization stocks. 

 Another large capitalization stock that declined substantially was 3M Co. 

(MMM), whose price chart is shown in Figure 23. 

Figure 23: Price Chart for 3M Co. (Ticker = MMM)

$65.00

$67.00

$69.00

$71.00

$73.00

$75.00

$77.00

$79.00

$81.00

$83.00

14:44:0014:44:1514:44:3014:44:4514:45:0014:45:1514:45:3014:45:4514:46:0014:46:1514:46:3014:46:4514:47:0014:47:1514:47:3014:47:4514:48:0014:48:1514:48:3014:48:4514:49:00

0

5

10

15

20

25

30

35

40

45

Thousands

Price Best Offer Best Bid Volume

Lowest price $67.98 

at 14:46:06

Sources: NYSE Trades and Quotes

The bid-ask spread for MMM stays quite narrow, and volume remains significant, 

even as the price declines from about $82 at 2:44 p.m. to a low of approximately $68 at 

2:46 p.m. Prior to reaching this low, the bid-ask spread over any given second 

dramatically widens and remains erratic before beginning a slow and choppy recovery. 

 MMM first declines from approximately $82.50 at 2:44 p.m. to approximately 

$71.00, then slowly begins to recover. Though this 14% decline was substantial, at 

approximately 2:48 p.m., the price declines sharply for a second time and hits a daily low 
 

53

of $67.98, resulting in a total decline from its 2:40 p.m. price of 18.39%, second only to 

PG among DJIA stocks. The price then suddenly climbs within a few seconds to 

approximately $77. As with PG, our analysis of the order book data should shed greater 

light on why MMM could appear to have recovered from the initial decline, then suffered 

such a sharp additional decline and rise. 

Figure 24:  Price Chart for Eaton Vance Tax­Managed Buy­Write Opportunities Fund (Ticker =

ETV)

$10.60

$10.80

$11.00

$11.20

$11.40

$11.60

$11.80

$12.00

$12.20

$12.40

$12.60

14:24:3014:24:3514:24:4014:24:4514:24:5014:24:5514:25:0014:25:0514:25:1014:25:1514:25:2014:25:2514:25:30

0

5

10

15

20

25

30

35

40

45

50

Thousands

Price Best Offer Best Bid Volume

Lowest price

$11.25 at

14:24:59

Sources: NYSE Trades and Quotes

 Figure 24 indicates that there is no activity in Eaton Vance Tax-Managed BuyWrite Opportunities Fund (ETV) from 2:24:30 p.m. through 2:24:43 p.m. at which time 

the bid drops by 6% rather quickly. Activity picks up again at about 2:24:57 p.m. as ETV 

partially recovers. This event occurred approximately 20 minutes prior to the main drop 

in broad markets. 
 

54

Figure 25:  Price Chart # 1 for Sotheby’s (Ticker = BID)

$0.00

$5.00

$10.00

$15.00

$20.00

$25.00

$30.00

$35.00

$40.00

$45.00

$50.00

14:44:0014:45:0014:46:0014:47:0014:48:0014:49:0014:50:0014:51:0014:52:0014:53:0014:54:0014:55:0014:56:0014:57:0014:58:0014:59:00

0

5

10

15

20

25

30

35

40

45

50

Thousands

Price Best Offer Best Bid Volume

Highest price

$99,999.9999

at 14:57:08

Sources: NYSE Trades and Quotes

In Figure 25, it can be seen that Sotheby’s (BID) is actively traded and has a 

narrow bid-ask spread from 2:44 p.m. through 2:49 p.m. after which volume is low but 

bid and ask quotes remain stable. However, after about 2:57 p.m. volume spikes 

dramatically and trades are executed at a high (presumably stub) quote of approximately 

$100,000. This event is plotted in more detail below. 
 

55

Figure 26: Price Chart #2 for Sotheby’s (Ticker = BID)

$0.00

$20.00

$40.00

$60.00

$80.00

$100.00

$120.00

14:57:0014:57:0114:57:0214:57:0314:57:0414:57:0514:57:0614:57:0714:57:0814:57:0914:57:1014:57:1114:57:1214:57:1314:57:1414:57:15

0

10

20

30

40

50

60

Thousands

Price Best Offer Best Bid Volume

Highest price

$99,999.9999

at 14:57:08

Sources: NYSE Trades and Quotes

As Figure 26 shows, BID trades through the national best offer multiple times 

between 2:57:05 p.m. and 2:57:12 p.m. This includes trades at approximately $100,000 

which is presumably a top-end stub quote. In contrast to the process in which bid-quotes 

for other stocks were shown to rapidly decline (which led to lower execution prices) here 

the highest offer price remained reasonable during a widening of the bid-ask spread, 

suggesting that the $100,000 trade occurred deeper into the order book. 

 

In contrast, many other stocks did not experience such substantial declines. Two 

such examples, IBM and Intel (INTC), are respectively shown below in Figures 27 and 

28. 
 

56

Figure 27: Price Chart for International Business Machines Corporation (Ticker = IBM)

$112.00

$114.00

$116.00

$118.00

$120.00

$122.00

$124.00

14:44:3014:44:4514:45:0014:45:1514:45:3014:45:4514:46:0014:46:1514:46:3014:46:4514:47:0014:47:1514:47:3014:47:4514:48:00

0

15

30

45

60

75

90

Thousands

Price Best Offer Best Bid Volume

Lowest price

$116 at 14:46:32

Sources: NYSE Trades and Quotes

It can be seen that IBM trades down from $122 at 2:44:30 p.m. to a low of $116 

(an approximate 5% loss) at 2:46:32 p.m. before rebounding to $120 by 2:48:00 p.m. 

The upward spikes in trade execution represent prices that were above the highest 

national best offer suggesting that these trades occurred deeper in the order book. Note 

that activity during the recovery period shows trade prices below the national best bid, 

but with very low volume.
 

57

Figure 28: Price Chart for Intel Corporation (Ticker = INTC)

$19.40

$19.60

$19.80

$20.00

$20.20

$20.40

$20.60

$20.80

$21.00

14:44:0014:44:1514:44:3014:44:4514:45:0014:45:1514:45:3014:45:4514:46:0014:46:1514:46:3014:46:4514:47:0014:47:1514:47:3014:47:4514:48:0014:48:1514:48:3014:48:4514:49:00

0

25

50

75

100

125

150

175

200

Thousands

Price Best Offer Best Bid Volume

Lowest 

price

$19.90 at 

14:47:40

Sources: NYSE Trades and Quotes

As indicated above, INTC has constant volume and narrow bid-ask spreads 

throughout its moderate 4% decline, though the highest offer quote was sometimes 

breached on the up-side suggesting trades being executed deeper into the order book. 

Table 16 presents summary information for each of the securities illustrated in the 

examples. The Historical Short Sale Ratio represents data from August 3, 2009 through 

April 23, 2010.35 None of the May 6 Short Sale Ratios are more than 1.5 standard 

deviations away from their Historical Average. 

                                                       

35 The “short sale ratio” is defined as the volume of short selling divided by total volume. 
 

58

Table 16: Summary Data for Single­Security Plots

Stock 

Symbol 

Listing 

Exchange 

Event 

Type 

Price ($) Time Price at 

2:00 

p.m. 

May 6 

Short 

Sale 

Ratio 

Historical 

Short Sale 

Ratio 

ACN NYSE Low 0.01 14:47:54 41.78 33% 37%

BID NYSE High 100K 14:57:08 32.15 51% 49%

EFG ARCA Low < 0.01 14:58:14 51.10 39% 39%

ETV NYSE Low 11.25 14:24:59 13.68 23% 32%

IBM NYSE Low 116.00 14:46:32 127.00 44% 41%

INTC NASDAQ Low 19.90 14:47:40 21.87 45% 48%

IWF ARCA Low < 0.01 14:47:28 49.65 62% 45%

MMM NYSE Low 67.98 14:46:06 85.64 41% 41%

PG NYSE Low 39.37 14:47:15 62.52 45% 39%

VTI ARCA Low 0.15 14:55:32 56.88 43% 53%

 We continue to evaluate any common drivers that might explain why trading for 

different securities exhibited different behaviors. Among a variety of factors, we are 

considering the effects of: 

Stop Loss Market Orders. As described further below, stop loss orders have 

stop prices that, for sell orders, are lower than current prices. If prices fall, these orders 

are intended to prevent losses from exceeding a certain amount (beyond the stop price) by 

liquidating a long position in the stock. When the stop price is reached, such orders turn 

into market orders to sell. In fast market conditions, stop loss market orders may cause 

trades at prices that are much lower than the “stop” price anticipated by an investor, 

because the market may have moved by a significant amount before the order is 

executed. They also could potentially, under certain circumstances, trigger a chain 

reaction of automated selling if they are used in significant numbers for a particular 

stock. For example, the triggering of one stop loss market order can trigger an automated 

sell market order that causes a price decline that, in turn, in the absence of liquidity 

provision, may trigger another stop loss market order at a lower level, and so on. 

NYSE’s LRP Mechanism. Another factor that we will examine closely is the 

effect of the NYSE’s LRP mechanism. As described further below, the NYSE’s trading 

system incorporates LRPs that are intended to dampen volatility in a given stock by 

temporarily converting from an automated market to a manual auction market when a 

price movement of a sufficient size is reached. In such a case, trading on the NYSE will 

“go slow” and pause for a time period to allow an opportunity for additional liquidity to 

enter the market. During an LRP, the NYSE will display a quotation that is not 

immediately accessible and can be bypassed, but is not required to be bypassed, by other 

trading venues and order routers. Some have suggested that LRPs exacerbated price 

volatility on May 6 by causing a net loss of liquidity as orders were routed to other 

trading venues. If accurate, this potentially could cause some NYSE securities to decline 

further than the broad market decline. Others believe that the LRP mechanism served to 
 

59

attract additional liquidity that helped soak up some of the excess selling interest in these 

securities on May 6. We are analyzing the effect of LRPs closely. 

B. Futures Markets 

The CFTC staff has conducted a preliminary review of activity in the futures 

markets to better understand the events that took place on May 6, 2010. The objective 

was to collect and analyze preliminary evidence that might be associated with possible 

causes of the events that occurred in futures markets on May 6, 2010, including, but not 

limited to erroneous activities (e.g., “fat finger” errors), cyber attacks, and significant 

system malfunctions. CFTC staff’s preliminary review has not, at this time, found 

evidence of erroneous activities, cyber attacks, or significant system malfunctions. 

Preliminary findings suggest that a confluence of economic events, signals from 

various other markets, and a marked increase in sell orders (in comparison to buy orders) 

culminated in a significant dislocation of liquidity in the E-mini S&P 500 futures 

contracts.36 This liquidity dislocation was also preceded by some reduction in activity of 

certain liquidity providers. 

The analysis focuses on trading and liquidity provision in the June 2010 E-mini 

S&P 500 futures contract. That single contract month in the E-mini S&P 500 comprised 

78.2 percent of the total volume of trading in the 12 most actively traded broad-based 

stock index futures contracts on May 6, 2010. 

1. Background 

Consistent with broad market trends on May 6, 2010, trading volume in the Emini S&P 500 futures was about 2.6 times greater than the average daily trading volume 

over the prior 30 days. On May 6, trading volume in the E-mini S&P 500 was the fifth 

highest daily volume over the past five years.37

Furthermore, the contract experienced a significantly higher level of trading 

during certain periods of the day. According to Figure 30,on May 6, the intraday-periodby-period trading volumes significantly exceeded the average trading volume for the 

same intra-day periods observed over the previous 30 days, especially between 2:00 p.m. 

and 3:30 p.m. 

The daily trading activity did not result in a significant increase in the number of 

futures contracts held by market participants at the end of May 6, 2010. This implies 

many investors participated in the market intraday, but on balance few investors 

                                                       

36 For more information on broad-based stock index futures, see Appendix B. 

37 Each of the four dates on which trading volume was greater occurred in September or October 

2008, during the financial crisis. During the week of the Lehman bankruptcy filing on September 

16, 17 and 18, 2008 trading volumes were 6.1 million contracts, 5.9 million contracts and 6.9 

million contracts, respectively. On October 10, 2008 trading volume was 5.9 million contracts. 
 

60

increased their position by the close of trading. Specifically, open interest in the June 

2010 E-mini S&P 500 futures contract increased by only 3.74%, to 2,688,328 contracts; 

at this level, daily open interest on May 6, 2010 did not rank among the highest five days 

over the previous 5 years.38An increase in open interest means there is a cumulative 

increase in the size of the market participants’ positions that remained open at the close 

of trading. 

In line with broad market trends, high trading volume in the June 2010 E-mini 

S&P 500 contract on May 6, 2010 coincided with significant changes in prices (price 

volatility). The daily price range in the E-mini S&P 500 was 112.75 points. This 

represents the second widest daily price range over the past five years. The other four of 

the top five widest price ranges over the past five years occurred during the financial 

crisis in the autumn of 2008, including the single largest daily price range of 115.5 points 

on October 28, 2008. Within the trading day, the widest range between high and low 

prices (calculated over 10 minute intervals) in the E-mini S&P 500—59.75 points—

occurred during the period 2:40 p.m. to 2:49 p.m. (Figure 29). 

Figure 29: CME E­mini S&P 500 Futures Trade Price and Volume

Source:  CME Group

According to the CME, over 250 Globex executing firms were active in routing 

E-mini S&P 500 futures contract orders into Globex during the hour beginning at 2 p.m., 

                                                       

38 Open interest means the total number of futures contracts that are not yet liquidated by offsetting 

transactions or cash settlement. 
 

61

including the period from 2:40 p.m. to 3:00 p.m. A Globex executing firm is an entity 

that is directly connected into Globex. Non-Globex executing firms access that trading 

platform through a Globex executing firm. 

Also during the hour of 2 p.m., Globex transactions in the E-mini S&P 500 

futures were recorded for 6,939 buy accounts, 6,873 sell accounts, 7,669 buy user IDs, 

and 7,564 sell user IDs. A buy (sell) account is a unique Globex account that executed 

one or more buy (sell) orders. A buy (sell) user ID is a unique operator ID (also referred 

to as a “Tag 50 ID”), identifying the party who entered the order on behalf of the account. 

A Tag 50 ID may be authorized to enter orders on behalf of multiple accounts. As well, a 

single account may have multiple authorized Tag 50 IDs. 

May 6, 2010 was also the first day in 2010on which the Globex system activated 

the Stop Logic functionality in any equity index futures market.39 Under CME rules, this 

functionality is initiated when the last transaction price would have triggered a series of 

stop loss orders that, if executed, would have resulted in a cascade in prices outside a 

predetermined ‘no bust’ range (6 points in either direction in the case of the E-mini S&P 

500 futures contract). The purpose of this functionality is to prevent sudden, cascading 

declines (or increases) in price caused by order book imbalances.40

At 2:40 p.m. the E-mini S&P 500 was trading at 1,113. Five minutes later at 2:45 

p.m. the E-mini S&P 500 had fallen another 57 points to 1,056.At 2:45:27 p.m., the Emini S&P 500 dropped 12.75 points over a period of 500 milliseconds on the sale of 

1,100 contracts by multiple market participants. This sequence of trades caused the 

market to trade down to an intraday low of 1,056. Further, at 2:45:27 p.m., the bid/ask 

spread in the E-mini S&P 500 market widened 6.5 points, or 26 ticks. This triggered the 

Globex ‘Stop-Logic,’ sending the E-mini S&P 500 into a reserve state at 2:45:28 p.m. 

The reserve state held execution of any transactions for five seconds. This hold allowed 

enough orders to flow into the market so that the next executed trade would be within six 

points of the last trade.41At 2:45:33 p.m. the E-mini S&P 500 exited its Stop-Logic 

reserve state.42

Stop Logic functionality was also triggered on May 6 in two currency futures 

contracts, the Japanese Yen and British Pound contracts. Across all CME Group equity 

index futures markets, the Stop Logic functionality was activated on seven occasions in 

2009, on 18 occasions during 2008 (a year with greater market volatility due to the 

economic crisis), and on three occasions in 2007. Fourteen of these 29 activations in 

equity index futures, including the one on May 6, occurred in the E-mini S&P 500 

                                                       

39 For more information on electronic trading, order display and order entry, see Appendix B.4, B.5 

and B.8. 

40 For more information, see Appendix B.10 and B.11. 

41 If at the end of those five seconds there were no orders that would result in such a transaction, the 

market would have been held an additional five seconds. 

42 Upon exiting the reserve state, 1,753 contracts were traded at a price of 1056.75. The E-mini S&P 

500 began to recover at that point. 
 

62

contract. Save for the unusual circumstances of the Fall of 2008, Globex activates Stop 

Logic an average of five times per year across all equity index futures products, and an 

average of approximately three times per year in the E-mini contract. All Stop Logic 

functionality activations in CME equity index futures markets from 2007 through the 

present are listed in 

Table 17. 

Table 17: CME Equity Index Futures Stop Logic Events by Date: 2007‐2010 

Year Date Contract Contract Name Time 

(Central 

Time) 

Total 

9/18/2007 ESU7 E MINI S&P 500 1:15 PM 1 

10/31/2007 EMDZ7 E-MINI MID CAP 1:14 PM 1 

2007 

 

 

12/24/2007 SPH8 BIG S&P 500 6:52 AM 1 

2007 Total 3 

2008 1/14/2008 ESH8 E MINI S&P 500 1:01 AM 1 

 1/21/2008 SPH8 BIG S&P 500 2:12 AM 1 

 ESH8 E MINI S&P 500 2:12 AM 1 

 3/16/2008 ESH8 E MINI S&P 500 6:14 PM 1 

 6:17 PM 1 

 7:06 PM 1 

 3/17/2008 ESH8 E MINI S&P 500 2:50 AM 1 

 7/10/2008 NQU8 E MINI NASDAQ 100 11:01 PM 1 

 9/14/2008 NQZ8 E MINI NASDAQ 100 5:00 PM 1 

 9/16/2008 ESU8 E MINI S&P 500 1:14 PM 1 

 9/25/2008 SPZ8 BIG S&P 500 10:45 PM 1 

 10/6/2008 SPZ8 BIG S&P 500 3:30 PM 1 

 10/9/2008 ESZ8 E MINI S&P 500 7:21 PM 1 

 10/17/2008 ESZ8 E MINI S&P 500 3:01 AM 1 

 10/29/2008 ESZ8 E MINI S&P 500 3:43 PM 1 

 11/3/2008 SPZ8 BIG S&P 500 7:22 AM 1 

 11/13/2008 ESH9 E MINI S&P 500 11:59 AM 1 

 11/25/2008 SPZ8 BIG S&P 500 5:45 AM 1 

2008 Total 18 

2009 1/9/2009 SPH9 BIG S&P 500 7:30 AM 1 

 2/27/2009 SPH9 BIG S&P 500 7:20 AM 1 

 2/28/2009 ESZ9 E MINI S&P 500 10:32 AM 1 

 3/6/2009 ZDH9 BIG DOW ($10) 7:30 AM 1 

 3/17/2009 NQM9 E MINI NASDAQ 100 1:17 PM 1 
 

63

 4/23/2009 YMM9 E MINI DOW ($5) 2:53 PM 1 

 12/17/2009 NQH0 E MINI NASDAQ 100 8:57 AM 1 

2009 Total 7 

2010 5/6/2010 ESM0 E MINI S&P 500 1:45 PM 1 

2010 Total 1 

Total: 2007-2010 29 

Source:  CME Group

Although the triggering of the Stop Logic functionality in the E-mini S&P 500 

futures contract is not unprecedented, the events of May 6 caused significant public 

concern about the functioning of financial markets. Previous Stop Logic events occurred, 

including during the financial crisis of 2008, when liquidity concerns played a key role. 

Consequently, CFTC staff has conducted an analysis of trading activity and liquidity 

provision in the June 2010 E-mini S&P 500 futures contract during 2:30 p.m. to 3:00 

p.m. – the period of the day when trading volume and transaction prices were particularly 

volatile. 

2. Role of Liquidity in Markets 

Liquidity reflects the ease with which certain amounts of an asset can be bought 

or sold without exerting a significant effect on its price. Higher market liquidity can be 

interpreted as a greater collective willingness to execute orders at given prices. 

Market liquidity is not directly observable. In addition, market liquidity has 

multiple dimensions that are hard to capture by a single indicator. CFTC staff reviewed 

multiple indicators of liquidity, including, but not limited to, trading volume, bid/offer 

spread, and depth. High liquidity may manifest itself as high trading volume, narrow 

bid/offer spreads, and/or high depth of the order book at successive quotes. 

As discussed below, preliminary analysis shows that between 2:30 p.m. and 3:00 

p.m., trading volume spiked, bid/offer spreads widened, and depth declined. The latter 

two observations are consistent with a significant decline in liquidity with the bulk of that 

decline occurring between 2:42 p.m. and 2:45 p.m. 

a) Trading Volume 

CFTC staff has analyzed trading volume and transaction prices for the June 2010 

E-mini S&P 500 futures contract during the period 2:30 p.m. to 3:00 p.m. on May 6, 

2010.Figure 30 presents transaction prices and trading volume for 10 second intervals 

from 2:30 p.m. to 3:00 p.m. for the June E-mini S&P 500 contact on May 6, 2010. 

According to Figure 1, between 2:30 p.m. and approximately 2:45 p.m., volume rose 

significantly while prices fell. Between 2:45 p.m. and 3:00 p.m. volume fell and prices 

rose. 
 

64

Figure 30: Price and Trading Volume in the June 2010 E­mini S&P 500 Futures Contract

Source:  CME Group

During the 30-minute period from 2:30 p.m. to 3:00 p.m., trading volume was 

about 10 times the average daily trading volume for the same intraday time period 

calculated over the prior 30 days. High trading volume by itself can be interpreted as an 

indicator of improved liquidity. However, Figure 30shows that high trading volume was 

accompanied by significant volatility of trading volume. This suggests a dislocation of 

market liquidity, with high volume fluctuations at the same time that orders are executed 

deep into the limit order book. Consequently, liquidity indicators based on the 

characteristics of the limit order book may provide additional information about the 

liquidity dynamics during 2:30 p.m. to 3:00 p.m. on May 6, 2010. 

b) Bid/Offer Spread 

The bid/offer spread is a liquidity indicator based on the characteristics of the 

limit order book. Specifically, the bid/offer spread is calculated as the difference 

between the highest quoted price to buy (bid) and the lowest quoted price to sell (offer or 

ask) one or several contracts or securities. This price difference is a measure of the cost 

paid by a buyer or a seller who wishes to transact immediately. Similarly, the second, 

third, fourth, fifth best bid and offer prices represent transaction costs to the buyer and 

seller willing to buy at increasingly lower prices and sell at increasingly higher prices. 

Figure 31presents the bid/offer spreads for the first best and fifth best quotes of 

the June 2010 E-mini S&P 500 specifically focusing on the period of 2:43 p.m. to 2:48 

p.m. along with transaction prices. The spread is measured in ticks—minimum price 

increments; for the E-mini S&P 500 contract the tick is equal to 0.25 point. The smallest 

bid/offer spread is one tick (0.25 point) and the smallest spread between the fifth best 
 

65

quotes is 9 ticks (2.25 points).43 Until approximately 2:45 p.m., both spreads were at 

their minimums, as is most often observed in this market. At 2:45:28 p.m., the best 

bid/offer spread widened to 26 ticks (6.5 points). At this time, Globex Stop Logic 

triggered a 5-second reserve state in the E-mini S&P 500 contract. Following the reserve 

state, the first and fifth best quote spreads increased to the period maxima of 

approximately 11 ticks (2.85 points) and 33 ticks (8.25 points), respectively.44 By 

2:50:40 p.m., both spreads declined to about 1 and 9 ticks (0.25 and 2.25 points), 

respectively. 

Source:  CME Group

c) Depth 

Depth is another liquidity indicator based on the size of orders in the limit order 

book. Depth is calculated as the sum of quantities of the orders resting at a particular 

price point—e.g., best bid or offer, second, third, fourth or fifth best bid or offer—in the 

limit order book. High depth (resting orders) on both sides of the limit order book may 

(but need not) result in higher trading volume (executed orders). 

                                                       

43 Bid/offer spread between 2:30 p.m. and 2:43:10 p.m. and 2:48:10 p.m. and 3:00 p.m. are at their 

minimums. 

44 These spread measurements are graphed at 10 second intervals, with each data point representing 

the average of all quotes within a 1 second period. 

Figure 31: Bid/Offer Spread (in Ticks) and Price in the June 2010 E­mini S&P 500 Futures

Contract
 

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Figure 32 illustrates the depth at the fifth best bid and offer quotes between 2:30 

p.m. and 3:00 p.m. According to Figure 32, significant order imbalances existed between 

orders to buy and orders to sell. In addition, around 2:45 p.m., depth declined 

dramatically, but the limit order book became approximately balanced (orders to sell 

became approximately equal to orders to buy), which is its typical state. 

Figure 32: Bid/Offer Quantities: 5th Best in the

June 2010 E­mini S&P 500 Futures Contract

Source:  CME Group

3. Analysis of Large Traders 

In order to further analyze the liquidity dynamics between 2:30 p.m. and 3:00 

p.m., CFTC staff examined the activities of large traders. In the preliminary analysis 

below, we report (1) the role of liquidity providers (six accounts, as defined below) and 

(2) activity of the ten largest traders by volume. 

First, Figure 33 presents the total transaction sides45 of two groups of market 

participants: liquidity providers and liquidity takers. 

                                                       

45 A side of a transaction means the account was either the buyer or the seller in a transaction. Total 

volume is equal to half of all transaction sides. To convert transaction sides to volume for a group 

of accounts, one must also eliminate half of the sides of trades transacted within the group of 

accounts (that is, not with accounts outside of the group). 
 

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Liquidity providers are traders that are routinely present in the market to both buy 

and sell futures contracts, facilitating rapid execution of transactions. In electronic limit 

order markets such as Globex, where the E-mini S&P 500 futures contract is traded, there 

are no designated liquidity providers (that is, no trader has an obligation to provide bid 

and ask quotations on demand). Thus, for the purpose of this preliminary analysis, CFTC 

staff classified liquidity providers by their activity in the markets.46

CFTC staff classified six accounts as liquidity providers. These six accounts 

participated in about 50 percent of all transaction sides between 2:30 p.m. and 2:34 p.m. 

The remaining 4,573 accounts (of the total 4,579 accounts transacting between 2:30 p.m. 

and 3:00 p.m.) are defined as liquidity takers. 

CFTC staff examined the behavior of liquidity providers during the time period 

2:30 p.m. to 3:00 p.m. and observed that starting at approximately 2:35 p.m. liquidity 

providers began limiting their trading activity as measured by transaction sides in 

comparison to liquidity takers (Figure 33).47 By 2:45:28 p.m., liquidity providers 

accounted for 46 percent of all transaction sides, lower than their participation percentage 

between 2:30 p.m. and 2:34 p.m. By 3:00 p.m. the liquidity providers accounted for 41 

percent of transaction sides. The decline in the participation of liquidity providers in 

executed transactions can be interpreted as a partial withdrawal of liquidity by these six 

providers during a period of significant price movement. 

                                                       

46 For the purposes of this analysis, liquidity providers are defined as follows: from the accounts that 

were both one of the 10 largest long gross volume accounts and 10 largest short gross volume 

accounts, CFTC staff selected the accounts that had a net position change of no more than 150 

contracts (long or short) during the time period 2:30 p.m. to 2:45 p.m. 

47 CFTC staff confirmed that between 2:42 p.m. and 2:45 p.m. that several additional accounts 

(belonging to some of the most active traders) ceased trading. Furthermore, CFTC staff confirmed 

through trader interviews that several accounts belonging to some of the most active traders ceased 

trading within seconds after the Stop Logic functionality was triggered and did not return to the 

market until later. A trader may transact through multiple accounts in Globex. 
 

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Figure 33: Cumulative Number of Transaction Sides of  

Liquidity Providers and Liquidity Takers in the June 2010 E­mini S&P 500 Futures Contract

Source:  CME Group and CFTC Staff Calculation

Second, CFTC staff reviewed the activity of the ten largest traders by net volume 

and by gross volume, in order to ascertain whether there were significant imbalances 

between large buyers and sellers in the market. For two intraday time periods—2:30 to 

2:45 p.m. and 2:46 to 3:00 p.m.—the net volume was computed for each account in the 

E-mini S&P 500 June 2010 futures contract.48 During the period from 2:30 to 2:45 p.m., 

the top 10 net buying accounts bought 51,526 contracts more than they sold. The top 10 

net selling accounts sold 72,186 contracts more than they bought. During the period from 

2:46 to 3:00 p.m., the top 10 net buying accounts bought 49,180 contracts more than they 

sold. The top 10 net selling accounts sold 67,544 contracts more than they bought. 

In addition, CFTC staff identified the top ten most active accounts by gross 

volume between 2:00 p.m. and 3:00 p.m. Of those ten, nine trading accounts executed 

trades on both the long and short side of the market. For these trading accounts, there 

was a relative balance of activity between the long and short sides of the market. 

                                                       

48 The numbers reported are the total net volume for accounts with the 10 largest net buy volumes 

(“top 10 net buying accounts”) and, separately, the total net volume for accounts with the 10 

largest net sell volumes (“top 10 net selling accounts”). Net volume for an account was calculated 

as the total buy volume minus the total sell volume in the time period. 
 

69

One out of the top ten trading accounts only entered orders to sell. That trader 

entered the market at around 2:32 p.m. and finished trading by around 2:51 p.m. The 

trader’s short futures position represented on average, nine percent on the volume traded 

during that period. The trader sold on the way down and continued to do so even as the 

price level rose. 

We are continuing to analyze trading activity, including conducting interviews 

with market participants to collect further data. 

4. Preliminary Findings 

The quantitative evidence presented above suggest that a confluence of economic 

events, market forces, and trading system functionality led to a significant dislocation of 

liquidity in the June 2010 E-mini S&P 500 futures contract sometime between 2:30 p.m. 

and 3:00 p.m. on May 6, 2010. 

Prior to that time, a number of economic events and market developments led to a 

broad-based market desire to lessen risk exposures. This translated into a downward 

movement in prices across financial markets in conjunction with significant trading 

volume. At or about 2:30 p.m., the electronic limit order book in the E-mini S&P 500 

futures market exhibited a significant imbalance of sell orders and buy orders. In the 

backdrop of declining prices, this imbalance appears to have contributed to a sudden 

liquidity dislocation despite increased trading volume. At approximately 2:45 p.m., 

several sell orders executed deep into the limit order book, which coincided with a 

significant loss of depth, triggering the Stop Logic functionality. The Stop Logic 

functionality in the E-mini S&P 500 contract has been triggered a number of times in the 

past few years, including several times during the financial crisis in the fall of 2008, 

when market conditions may have resembled those seen on May 6, 2010. Activation of 

the Stop Logic functionality on May 6, 2010, initiated a five second pause in trading in 

the E-mini S&P 500 futures contract. After the five second pause, the limit order book 

became more balanced, which is its typical state, and the price of the E-mini S&P 500 

futures contract recovered. 

C. Clearance and Settlement 

1. Securities Markets 

Securities clearing agencies are self-regulatory organizations that are required to 

register with the SEC under Section 17A of the Securities Exchange Act. There are two 

types of securities clearing agencies – clearing corporations and depositories. 

Clearing corporations compare member transactions (or report to members the 

results of exchange comparison operations), clear those trades and prepare instructions 

for automated settlement of those trades, and often act as intermediaries in making those 

settlements. Clearing corporations include the National Securities Clearing Corporation 

(“NSCC”), a subsidiary of the Depository Trust & Clearing Corporation (“DTCC”), and 
 

70

the Options Clearing Corporation (“OCC”). Depositories hold securities in bulk form for 

their participants and maintain ownership records of the securities on their own books. 

Currently, the Depository Trust Company, a subsidiary of DTCC, is the primary U.S. 

securities depository. 

There were no significant processing issues at DTCC or OCC as a result of the 

market events on Thursday, May 6. The clearing agencies’ systems operated in an 

orderly manner both during and subsequent to those market events. 

Collection of funds due to the clearing agencies on the morning of Friday, May 7, 

occurred without incident as all clearing fund participants met their payment obligations 

on time. 

To accommodate the late submission of trade data by exchanges, clearing 

agencies, where necessary, delayed end-of-day processing on Thursday, May 6. This was 

particularly the case at the DTCC subsidiary NSCC because of the large number of 

cancelled trades in the equities markets. Processing was completed at OCC only slightly 

later than usual. 

The market volatility and price decreases on Thursday, May 6, also resulted in 

substantially higher margin and clearing fund requirements at the clearing agencies on 

Friday, May 7. The requirements were calculated pursuant to the risk-based margin 

methodologies in place at the clearing agencies and in accordance with clearing agency 

rules and procedures. All margin and clearing fund requirements were met by clearing 

participants Friday morning on time. 

2. Futures Markets 

The Commodity Exchange Act (“CEA”) requires all CFTC regulated designated 

contract markets (“DCM”) to have all contracts that trade on the DCM to be cleared and 

settled by a CFTC registered derivatives clearing organization (“DCO”). The DCO 

functions as the central counterparty and guarantor for the positions that result from all 

contracts traded on the DCM. This means that the DCO is the long to each short position 

and the short to each long position in all contracts that it clears. DCOs deal exclusively 

with their clearing participants. Any market participant that is not a clearing member of a 

particular DCM must have its positions carried by a clearing member. The DCO for CME 

is the CME Clearing House while the DCO for ICE Futures US is ICE CLEAR US. 

 One of the critical functions that each CFTC registered DCO performs is the 

removal of debt obligations among its clearing members at least at the end of the trading 

session for a given trade date. This is accomplished by independently determining a 

settlement (or marking) price for each contract that is cleared and marking all open 

positions to that price. The DCO collects cash from clearing members that have lost 

money on their positions and pays it to clearing members that have gained money on 

their positions. 
 

71

 With respect to the trading that took place on May 6 at CME and ICE Futures 

U.S., the clearing and settlement processes worked effectively and without incident. 

 The amount that the CME collected and paid to its clearing members as a result of 

the end-of-day mark-to-market calculation for all contracts cleared by CME was 

$4,073,195,863. Of this sum, $2,902,837,844 was collected and paid in the customer 

origin while $1,170,358,019 was collected and paid in the house origin. 

 The amount collected and paid by ICE CLEAR US to its clearing members as a 

result of the end-of-day mark-to-market calculation was $749,680,556. Of this sum, 

$120,701,044 was collected and paid in the customer origin while $628,979,512 was 

collected and paid in the house origin. 

All payments to and from each DCO were met on time. 
 

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V. NEXT STEPS 

A. Areas for Further Analysis 

1. Securities Markets 

A crucial area for further analysis is how sudden demands for liquidity 

(particularly by sellers in a rapidly declining market) are transmitted among the various 

securities, options, and futures markets and products. In today’s highly automated and 

low-latency markets, the links between the various related markets and products are 

extremely tight. 

 To conduct this analysis, we are undertaking a detailed market reconstruction, so 

that cross-market patterns can be detected and the behavior of stocks or traders can be 

analyzed in detail. Reconstructing the market on May 6 from dozens of different sources 

and calibrating the time stamps from each source to ensure consistency across all the data 

is consuming a significant amount of SEC staff resources.49 The data are voluminous, 

and include hundreds of millions of records comprising an estimated five to ten terabytes 

of information. On May 6, there were over 17 million trades between 2:00 p.m. and 3:00 

p.m. alone. Overall, the markets processed 10.3 billion shares in NYSE stocks alone that 

day. By contrast, the key day in the 1987 Market Break Study involved a trading session 

processing a little over 600 million shares in NYSE stocks. 

SEC staff is investigating plausible explanations of events, forming testable 

hypotheses and using the data available to us to assess them. There are many challenges 

to completing this analyses. The size and complexity of our markets and those of related 

markets, the effects of computerized trading, the diversity and opacity of trading 

strategies and linkages among financial instruments make this a complicated task. 

A theory of the May 6 events should attempt to explain a number of the 

preliminary findings outlined in this report, to the extent they are confirmed by a more 

                                                       

49 The SEC has obtained quotation and last-sale information produced by the Consolidated Tape 

plans, which cover all executions in NMS stocks, regardless of whether they occurred on an 

exchange or over-the-counter. The plans information also contains all top-of-book quotations (i.e., 

the best orders or quotations in each listed equity security at each market at each point in time). 

However, the Consolidated Tape plans does not include orders that were outside the top of book, 

which constitute the vast majority of orders placed on any trading day. Most of these orders never 

execute and are canceled. Under current rules, there is no single record of such orders across the 

different markets. The relevant sources for this information include: 

• OATS. The Order Audit Trail System (OATS) was established by NASD in 1996 and 

captures information on orders in Nasdaq-listed securities. 

• OTS. The Order Tracking System (OTS) was established by the NYSE in 1999 and 

captures information on orders in equity securities listed on NYSE and NYSE Amex. 

The OTS is a system for gathering information by a request that can take ten days to fill. 

• Individual exchanges. Each exchange has its own systems to record information about 

orders placed and executed on its market, regardless of which exchange lists the security. 
 

73

exhaustive analysis, as well as any other facts uncovered. Among other things, a theory 

should explain: 

• the sudden decline and sudden rebound in stocks generally; 

• significant intraday negative returns of certain issues; 

• the intraday lows of nearly zero in approximately 200 issues (shown in 

Figure 8), and the heightened levels of short selling that occurred at or 

near the intraday low; 

• the extreme intraday highs of a significant number of issues, particularly 

among ETFs; and 

• the disproportionate representation of ETFs among extreme returns. 

A central component of this research is to understand the basic facts surrounding 

the event period and examine data from key additional sources. This exploratory work 

will guide the staff in forming causal hypotheses. For example, we will likely examine in 

more detail options data, including data on options transactions and quotes to better 

understand the role that participants in this market may have played.50 We also will likely 

examine existing data on institutional and mutual fund holdings, as well as data from 

broker-dealers that will help attribute trades to specific brokerage accounts. In addition, 

we will examine trade and order characteristics to determine whether specific order types 

played a role in the breakdown of the price discovery mechanism. 

Another key component of our analysis is to deepen our understanding of the 

behavior of groups of market participants. We, for example, will continue to examine the 

role of providers of liquidity, including market participants who have formal obligations 

under the federal securities laws or SRO rules. To the extent that data is available, we 

will seek to understand the impact of traders following high-frequency or algorithmic 

trading strategies. Many proprietary trading firms engage in automated strategies that 

continually monitor the various markets and products for disparities in prices. When the 

trading systems for these firms spot such disparities, they can generate in microseconds 

an enormous volume of orders that are intended to capitalize on these disparities. We 

would also consider examining the activities of ETF Authorized Participants in order to 

understand what, if any role, they played, in the markets of May 6. Additionally, our 

analysis to date has encompassed information about both ETF and non-ETF ETPs, but 

has not yet ascertained whether or not there are significant differences between the 

trading experiences of the two. 

                                                       

50 Our initial options analysis suggests that there were not triggers originating from the options 

markets. 
 

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2. Futures Markets 

a) Additional Analysis of Large Traders and Review of OTC 

Swaps 

CFTC staff will continue reviewing information from a special call on over 40 

large traders for their trading activity in the E-mini S&P 500 and Russell 2000 futures 

contracts on May 6, 2010. A special call is a CFTC directive to a trader holding a 

reportable position to furnish any pertinent information concerning the trader’s positions, 

transactions, or activities.51 A reportable position in the E-mini S&P 500 futures contract 

is 1,000 contracts.52 Staff also will continue reviewing information from a special call to 

swap dealers about their activity in over-the-counter broad-based security index 

derivatives markets on May 6, 2010. Staff also will continue its detailed review of trader 

activity on May 6 through a comprehensive examination of trade-register data. To date, 

staff has received over 25 gigabytes of data in over 307,000 files, with more data 

expected. 

b) Additional Analysis of May 6 Activity 

CFTC staff will continue to scrutinize a broad range of existing evidence, collect 

new evidence, and update its analysis of the events of May 6, 2010. 

CFTC staff will also continue our analysis of high frequency traders active in the 

E-mini S&P 500 futures on May 6, 2010. 

3. Coordinated Analysis 

As reported above, related financial instruments appeared to experience 

significant volatility, including the sharp decline and recovery in close proximity. This 

suggests the need to study the linkages between correlated assets in the equities (single 

stocks, mutual funds and ETFs), options and futures markets. The study could partly 

focus on examining cross-market linkages by analyzing trading in stock index products 

such as equity index futures, ETFs, equity index options, and equity index OTC 

derivatives using, to the extent practicable, market data, special call information, and 

order book data. The growth, depth, and use of instruments in each of these markets to 

serve as intra- and cross-market hedges suggest that regulators need to better understand 

the linkages between these markets. 

Given the role that the two agencies play in overseeing key related markets, the 

staff of the CFTC and SEC should coordinate on a study designed to shed further light on 

these linkages. Such a study may significantly help design a coordinated system of 

meaningful and appropriate pauses and halts for these interlinked markets. 

                                                       

51 17 CFR 18.05. 

52 17 CFR 15.03. 
 

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B. Potential Regulatory Responses 

The Commissions are considering whether modifications to the existing marketwide circuit breakers are warranted in light of the events of May 6. Any such 

modifications should be done in a coordinated manner between the securities and futures 

markets. 

An important lesson from the events of May 6 is the need to better understand 

cross-market linkages between trading venues for exchange-traded funds, equity index 

futures, and equity index options—instruments used by investors to manage their 

exposures in the face of broad market movements. A thorough understanding of crossmarket linkages will better inform the design of a coordinated system of meaningful and 

appropriate pauses and halts for these interlinked markets. 

In connection with better understanding inter-market mechanisms, it is also 

important for the agencies to review the various mechanisms used and designed by 

exchanges to protect orderly markets. As the study of the May 6 events continues, 

attention should be given to the adequacy of current mechanisms under different stress 

situations. 

1. Securities Markets 

As noted above, the SEC is taking a number of steps to identify the cause or 

causes of the May 6 market disruption as well as factors that may have exacerbated that 

event, and to develop regulatory initiatives to help prevent a recurrence. 

a) Implement Stock-by-Stock Circuit Breakers 

The SEC staff is working with the stock exchanges and FINRA to promptly 

develop and implement a cross-market “circuit breaker” mechanism to be applied on a 

stock-by-stock basis. Although the prices of many stocks on May 6 declined in 

proportion with the broader market decline that occurred in securities and futures index 

products, the prices of many other individual stocks declined much more before returning 

near to the prices at which they were trading prior to the precipitous decline. 

A uniform circuit breaker rule, which would briefly pause trading across the 

securities markets when the price of a security has rapidly declined over a short period of 

time, should make a recurrence of a severe market disruption, such as the one that 

occurred on May 6, much less likely. 

b) Market Orders 

As noted above, some of the most disturbing executions on May 6 likely resulted 

from the use of market orders. Market orders – particularly stop loss orders that convert 
 

76

to market orders – are popular with certain investors, including retail investors, and it is 

possible such investors may have been on the losing side of a number of these trades. 

We are considering ways to address the risks of market orders, and their potential 

to contribute to sudden price moves. Areas under consideration include: (1) requiring 

market order “collars,” thereby effectively converting market orders into limit orders; (2) 

prohibiting or limiting the use of market orders; (3) requiring broker-dealers to 

specifically warn retail customers about the risks of market orders, particularly in volatile 

markets; and (4) pursuing investor education initiatives as to the risks of market orders. 

c) Market Making Obligations and Stub Quotes 

Liquidity providers to, or “the other side” of, the extraordinarily erroneous trades 

seen on May 6 appears in many cases to be “stub” quotes (e.g., a $0.01 bid) of market 

makers that effectively had pulled out of the market. Market makers maintain these 

nominal quotes to meet exchange requirements that they maintain a two-sided quote 

throughout the trading day. We are considering steps to deter or prohibit stub quotes, 

including: (1) requiring all market makers to maintain bona fide quotes that are 

reasonably related to the market, perhaps using objective parameters that are consistent 

across markets; or (2) alternatively, relaxing requirements that market makers maintain a 

two-sided quote throughout the day, and thereby obviate the need for market makers to 

post stub quotes that could be executed against in severe market conditions. 

d) Revise Procedures for Breaking Clearly Erroneous Trades 

The SEC expects the exchanges and FINRA to improve the process for breaking 

“clearly erroneous” trades. Of course, the primary objective should be a market structure 

that minimizes the need to correct erroneous trades, and the initiatives described above 

should do that. To the extent any erroneous trades continue to occur, however, they 

should be resolved promptly and consistently across markets through a transparent 

process with objective standards. The SROs are considering a specified percentage 

threshold away from the market price at which erroneous trades uniformly would be 

broken. This should provide market participants clarity and certainty as to whether their 

trades will stand in the event the market becomes particularly volatile. 

e) Current Initiatives to Strengthen Market Integrity 

The SEC had already undertaken a number of broader initiatives to strengthen the 

integrity our markets, even before the events of May 6. 

In January, the SEC published a concept release on equity market structure 

(“Market Structure Concept Release”)53 that highlighted many aspects of today’s highly 

automated markets and requested public comment on a wide variety of issues. The 

                                                       

53 See Securities Exchange Act Release No. 61358 (January 14, 2010), 75 FR 3594 (January 21, 

2010). 
 

77

Market Structure Concept Release was designed to further the SEC’s broad review of 

market structure to assess whether its rules have kept pace with, among other things, 

changes in trading technology and practices. 

The events of May 6 implicate a number of issues raised in the Market Structure 

Concept Release. For example, the Release asked whether the current market structure 

appropriately minimizes the short-term volatility that can be harmful to long-term 

investors. It asked whether the relatively good performance of the market structure in 

2008 indicated that systemic risk was appropriately minimized in the current market 

structure and, if not, what further steps the SEC should take to address systemic risk. 

Finally, it noted the dominant role of high-frequency trading firms in today’s market 

structure and observed that they had largely replaced the role of specialists and market 

makers with affirmative and negative obligations for market liquidity and market quality. 

More specifically, the Market Structure Concept Release asked whether there is any 

evidence that proprietary firms increase or reduce the amount of liquidity provided to the 

market during times of stress. It also asked whether co-location conveyed any unfair 

advantage and discussed various types of short-term trading strategies, including 

“directional” strategies, such as “momentum ignition,” that could present serious 

problems in today’s market structure by exacerbating short-term volatility. 

We are also considering whether initiatives are warranted to address destabilizing 

short-term trading strategies, to the extent they contributed to the May 6 market 

disruption. For example, a variety of directional strategies that might be employed by 

proprietary trading firms are discussed in the Market Structure Concept Release. It is too 

early to know whether short-term professional trading strategies played any role in the 

events of May 6. If they contributed significantly to the precipitous decline, however, we 

must consider whether additional regulatory requirements are necessary to prevent such 

strategies from threatening the fairness and integrity of the markets. 

In February, moreover, the SEC adopted a short sale circuit breaker. That rule is 

designed to limit short selling where an individual stock is under stress and has 

experienced a decline of 10 percent from the previous day’s close. At that point, the 

restrictions of the rule provide assurances to investors that short sellers are not taking the 

stock down. In so doing, we believe that the rule will promote investor confidence. 

In addition, the SEC has published a series of concrete market structure proposals 

that are designed to strengthen the U.S. securities markets and to protect investors. These 

include the proposal to prohibit flash orders and the proposal to increase the transparency 

of “dark” pools of liquidity, as well as the market access proposal to strengthen brokerdealer risk management controls and the large trader reporting proposal to enhance the 

SEC’s surveillance and enforcement capabilities. These proposals are described in 

greater detail below. 
 

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(1) Market Access Proposal 

In January, the SEC proposed a rule that would require effective risk management 

controls for broker-dealers with access to markets, including those providing customers 

sponsored access to the markets. Our proposal would effectively prohibit the growing 

practice by some broker-dealers of providing “unfiltered” sponsored access, where a 

customer is permitted to directly access the markets using the broker-dealer’s market 

participant identifier but without the imposition of effective pre-trade risk management 

controls. All broker-dealers accessing the markets should implement controls to 

effectively manage the risks associated with this activity, and our proposal would 

unequivocally require them to do so. These risks include the potential breach of a credit 

or capital limit, the submission of erroneous orders as a result of computer malfunction or 

human error, and the failure to comply with regulatory requirements. Effective risk 

management controls for market access arrangements are necessary to protect the brokerdealer, the markets, the financial system, and ultimately investors. Such controls would 

help prevent trading activity that could trigger a severe market disruption. 

(2) Large Trader Reporting Proposal 

Last month, the SEC proposed to create a large trader reporting system that would 

enhance our ability to identify large market participants, collect information on their 

trades, and analyze their trading activity. To keep pace with rapid technological 

advances that have impacted trading strategies and the ways in which some market 

participants trade, the SEC must be able to readily identify large traders operating in the 

U.S. securities markets, and obtain basic identifying information on each large trader, its 

accounts, and its affiliates. In addition, to support its regulatory and enforcement 

activities, the SEC must have a mechanism to track efficiently and obtain promptly 

trading records on large trader activity. 

The current system for collecting transaction data from registered broker-dealers 

is generally utilized in more narrowly-focused investigations involving trading in 

particular securities, and is not generally conducive to larger-scale market reconstructions 

and analyses involving numerous stocks during periods of peak trading volume. In 

addition, existing tools often require weeks or longer to compile trading data to identify 

potentially large traders. The SEC needs to develop the tools necessary to readily 

identify large traders and be able to evaluate their trading activity is heightened by the 

fact that large traders, including certain high-frequency traders, are playing an 

increasingly prominent role in the securities markets. 

The proposed rule would enhance the SEC’s ability to identify those “large 

trader” market participants that conduct a substantial amount of trading activity in U.S. 

securities, as measured by volume or market value. In addition, the proposal would 

facilitate the SEC’s ability to obtain from broker-dealers records of large trader activity. 

By providing the SEC with prompt access to information about large traders and their 

trading activity, the proposed rule is intended to facilitate the SEC’s efforts in 
 

79

reconstructing market activity and performing analyses of trading data, as well as assist in 

investigations of manipulative, abusive, and other illegal trading activity. 

(3) Consideration of Consolidated Audit Trail Proposal 

As noted above, SEC staff have been working, in consultation with SROs and 

others, on a rule proposal that would require the SROs to jointly develop, implement and 

maintain a consolidated order tracking system, or consolidated audit trail. If adopted, this 

rule proposal should result in a continuous reporting mechanism for market participants 

that would capture the data needed for effective cross-market surveillance. The proposed 

changes would significantly improve the SEC’s ability to conduct timely and accurate 

trading analyses for market reconstructions and complex investigations, as well as 

inspections and examinations. For example, the proposed consolidated audit trail would 

enable the SEC to access in real time the majority of the data needed to reconstruct the 

type of market disruption that occurred on May 6, with remaining information available 

within a matter of days rather than weeks. 

2. Futures Markets 

a) Review of Electronic Trading and Market Access 

CFTC staff will also continue our analysis, already begun by our Office of Chief 

Economist, of liquidity provision in futures markets, with a particular focus on electronic 

trading. The subjects to be reviewed here include high frequency and algorithmic 

trading, automatic execution innovations on trading platforms, market access issues, and 

co-location. 

b) Review of Co-Location 

CFTC staff is considering a proposed rulemaking with respect to exchange colocation and proximity hosting services. The purpose of the proposed rule would be to 

ensure that all otherwise qualified and eligible market participants that seek co-location 

or proximity hosting services offered by futures exchanges have equal access to such 

services without barriers that exclude access, or that bar otherwise qualified third-party 

vendors from providing co-location and/or proximity hosting services. Another purpose 

of the proposal would be to ensure that futures exchanges that offer co-location or 

proximity hosting services disclose publically the latencies for each available 

connectivity option, so that participants can make informed decisions. 

c) Additional Analysis of Large Traders and Review of OTC 

Swaps 

The CFTC will continue reviewing information from a special call on major swap 

traders for their trading activity on May 6, 2010. A special call is a CFTC directive to a 

trader holding a reportable position to furnish any pertinent information concerning the 
 

80

trader’s positions, transactions, or activities.54 A reportable position in the E-mini S&P 

500 futures contract is 1,000 contracts.55 There will also be a review of special call 

information about the activity of swap dealers in over-the-counter broad-based security 

index derivatives markets on May 6, 2010. Staff also will continue its detailed review of 

trader activity on May 6 through a comprehensive examination of trade-register data. 

d) Automation of Account Identification 

CFTC staff will also be considering possible rules to enhance the CFTC’s 

surveillance capabilities. These measures include automation of the statement of 

reporting traders in the large trader reporting system and obtaining account ownership 

and control information in the exchange trade registers.56 These initiatives would 

increase the timeliness and efficiency of account identification, an essential step in data 

analysis. 

                                                       

54 17 CFR 18.05. 

55 17 CFR 15.03. 

56 17 CFR 18.04. 
 

Appendix A - 1 

APPENDIX A 

Overview of the Securities Market Structure 

A. The National Market System and Regulation NMS 

 In Section 11A of the Securities Exchange Act of 1934 (added to the Exchange 

Act in 1975), Congress directed the SEC to facilitate the establishment of a national 

market system for securities in accordance with specified findings and objectives. 

Congress recognized that the securities markets are an important national asset that must 

be preserved and strengthened, and that new data processing and communications 

techniques create the opportunity for more efficient and effective market operations. It 

mandated a national market system composed of multiple competing markets that are 

linked through technology. A national market system should be contrasted with a 

structure in which trading is confined to a single trading venue, such as one particular 

exchange. Congress determined that promoting competition among trading venues and 

giving as many market makers as possible an opportunity to provide liquidity in stocks 

would promote greater liquidity and price continuity than a single dominant trading 

venue. 

 Over the years, the SEC has sought to keep market structure rules up-to-date with 

continually changing economic conditions and technology advances. The most recent 

major updating of the national market system rules occurred in 2005, when the SEC 

adopted Regulation NMS.57 Regulation NMS addresses four areas: (1) a “trade-through” 

rule that prevents the execution of trades at prices that are inferior to a displayed and 

immediately accessible quotation on another trading venue; (2) an “access” rule that, 

among other things, promotes private linkages among market participants and trading 

venues; (3) a “sub-penny” rule that prohibits the display, ranking, or accepting of orders 

with sub-penny prices; and (4) amendments to the joint-industry plans for collecting and 

distributing consolidated market data to the public. 

 The trade-through rule58 is probably the most well-known aspect of Regulation 

NMS and arguably has affected the equities markets most significantly since it was 

adopted in 2005. The Regulation NMS trade-through rule eliminated a prior rule that 

benefited dominant exchanges with trading floors by protecting their manual quotations 

(that is, orders were required to be routed to the exchange in an attempt to access a 

manual quotation that could take as long as 10-20 seconds, rather than to another venue 

with an immediately accessible quotation at an inferior price). 

                                                       

57 See Securities Exchange Act Release No. 51808 (June 9, 2005), 70 FR 37496 (June 29, 2005) 

(“Regulation NMS Release”). 

58 17 CFR 242.611. 
 

Appendix A - 2 

 To compete under the new regulatory structure, all exchanges developed 

electronic systems that are capable of providing immediate responses to incoming orders 

and updating their quotations immediately. These systems enable the exchanges to 

display quotations that are protected against trade-throughs. Trade-through protection 

was designed to promote best execution and price stability by preventing one trading 

venue from ignoring the immediately accessible quotations of another trading venue in a 

downturn (as well as upturn). However, the trade-through rule does not protect a trading 

venue’s quotation if it is not immediately accessible. 

B. The Nature of Trading in the Current Equities Market Structure 

1. Trading Centers 

 At least partly as a result of Regulation NMS, trading in U.S-listed stocks has 

changed dramatically in recent years. Trading volume now is dispersed among many 

different trading venues. For example, the share of the New York Stock Exchange in the 

trading in NYSE-listed stocks declined from 79.1 percent in 2005 to 25.1 percent in 

2009. National securities exchanges and another type of trading venue, electronic 

communications networks (“ECNs”), both display quotations in the consolidated 

quotation data that is widely distributed to the public. In addition, two other types of 

trading centers exist –dark pools and broker-dealers that execute trades internally – 

neither of which display quotations in the consolidated quotation data. Nevertheless, 

more than 70 percent of volume continues to be executed by public trading venues that 

display quotations across a wide range of U.S-listed stocks. Figure 1 below sets forth the 

major types of trading venues, along with estimates of their trading volume in September 

2009:59

                                                       

59 Sources of estimated trading volume percentages: NASDAQ; NYSE Group; BATS; Direct Edge; 

data compiled from Forms ATS for 3d quarter 2009. 
 

Appendix A - 3 

Figure 1: Trading Centers and Estimated Percentage of Share Volume in NMS Stocks

1.0%

Other ECN

7.9%

Dark Pools

9.8%

Direct Edge

3.7%

Other Exchange

3.3%

NASDAQ OMX BX

9.5%

BATS

13.2%

NYSE Arca

17.5%

Broker-Dealer 19.4%

NASDAQ

14.7%

NYSE

NASDAQ NYSE NYSE Arca

BATS NASDAQ OMX BX Other Registered Exchange

ECN: 2 Direct Edge ECN: 3 Others Dark Pools Approximately 32

Broker-Dealer Internalization More than 200

a) Registered Exchanges 

 Registered exchanges (such as NASDAQ, NYSE, NYSE Arca and BATS, among 

others) must undertake self-regulatory responsibility for their members and file their 

proposed rule changes for approval with the SEC. These proposed rule changes publicly 

disclose, among other things, the trading services and fees of exchanges. 

 The registered exchanges all have adopted highly automated trading systems that 

can offer extremely high-speed, or “low-latency,” order responses and executions. The 

average response times at some exchanges, for example, have been reduced to less than 1 

millisecond.60 Many exchanges also offer individual data feeds that deliver information 

concerning their orders and trades directly to customers. To further increase speed in 

transmitting market data and order messages, many exchanges also offer co-location 

services that enable exchange customers to place their servers in close proximity to the 

exchange’s matching engine. 

 Registered exchanges typically offer a wide range of order types for trading on 

their automated systems. Some of their order types are displayable in full if they are not 

                                                       

60 See, e.g., BATS Exchange, Inc., 

http://batstrading.com/resources/features/bats_exchange_Latency.pdf (June 2009) (average latency 

(time to accept, process, and acknowledge or fill order) of 320 microseconds; NASDAQ, 

http://www.nasdaqtrader.com/trader.aspx?id=inet (December 12, 2009) (average latency (time to 

accept, process, and acknowledge or fill order) of 294 microseconds). 
 

Appendix A - 4 

executed immediately. Others are undisplayed, in full or in part. For example, a reserve 

order type will display part of the size of an order at a particular price, while holding the 

balance of the order in reserve and refreshing the displayed size as needed. In general, 

displayed orders are given execution priority at any given price over fully undisplayed 

orders and the undisplayed size of reserve orders.61

 In addition, many exchanges have adopted a “maker-taker” pricing model in an 

effort to attract liquidity providers. Under this model, non-marketable, resting orders that 

offer (make) liquidity at a particular price receive a liquidity rebate if they are executed, 

while incoming orders that execute against (take) the liquidity of resting orders are 

charged an access fee. Rule 610(c) of Regulation NMS caps the amount of the access fee 

for executions against the best displayed prices of an exchange at 0.3 cents per share. 

Exchanges typically charge a somewhat higher access fee than the amount of their 

liquidity rebates, and retain the difference as compensation. Sometimes, however, 

exchanges have offered “inverted” pricing and pay a liquidity rebate that exceeds the 

access fee. 

b) ECNs 

 ECNs, as well as dark pools (discussed below) are regulated as alternative trading 

systems (“ATSs”). The key characteristic of an ECN is that it provides its best-priced 

orders for inclusion in the consolidated quotation data, whether voluntarily or as required 

by Rule 301(b)(3) of Regulation ATS. In general, ECNs offer trading services (such as 

displayed and undisplayed order types, maker-taker pricing, and data feeds) that are 

analogous to those of registered exchanges. 

c) Dark Pools 

 Dark pools are ATSs that, in contrast to ECNs, do not provide their best-priced 

orders for inclusion in the consolidated quotation data. In general, dark pools offer 

trading services to institutional investors and others that seek to execute large trading 

interest in a manner that will minimize the movement of prices against the trading interest 

and thereby reduce trading costs. There are approximately 32 dark pools that actively 

trade NMS stocks.62 ATSs (both dark pools and ECNs) fall within the statutory 

definition of an exchange, but are exempted if they comply with Regulation ATS. 

                                                       

61 See, e.g., BATS Exchange, Inc., Rule 11.12 (equally priced trading interest executed in time 

priority in the following order: (1) displayed size of limit orders; (2) non-displayed limit orders; 

(3) pegged orders; (4) mid-point peg orders; (5) reserve size of orders; and (6) discretionary 

portion of discretionary orders); NASDAQ Rule 4757(a)(1) (book processing algorithm executes 

trading interest in the following order: (1) displayed orders; (2) non-displayed orders and the 

reserve portion of quotes and reserve orders (in price/time priority among such interest); and (3) 

the discretionary portion of discretionary orders. 

62 Data compiled from Forms ATS submitted to Commission for 3d quarter 2009. Some OTC 

market makers offer dark liquidity primarily in a principal capacity and do not operate as ATSs. 

For purposes of this report, such trading centers are not defined as dark pools because they are not 

ATSs. They may, however, offer electronic dark liquidity services that are analogous to those 

offered by dark pools. 
 

Appendix A - 5 

Regulation ATS requires ATSs to be registered as broker-dealers with the SEC, which 

entails becoming a member of the Financial Industry Regulatory Authority (“FINRA”) 

and fully complying with the broker-dealer regulatory regime. Unlike a registered 

exchange, an ATS is not required to file proposed rule changes with the SEC or otherwise 

publicly disclose its trading services and fees. ATSs also do not have any self-regulatory 

responsibilities, such as market surveillance. 

 Dark pools can vary quite widely in the services they offer their customers. For 

example, some dark pools, such as block crossing networks, offer specialized size 

discovery mechanisms that attempt to bring large buyers and sellers in the same NMS 

stock together anonymously and to facilitate a trade between them. The average trade 

size of these block crossing networks can be as high as 50,000 shares.63 Most dark pools, 

though they may handle large orders, primarily execute trades with small sizes that are 

more comparable to the average size of trades in the public markets, which was less than 

300 shares in July 2009.64 These dark pools that primarily match smaller orders (though 

the matched orders may be “child” orders of much larger “parent” orders) execute more 

than 90% of dark pool trading volume.65 The majority of this volume is executed by dark 

pools that are sponsored by multi-service broker-dealers. These broker-dealers also offer 

order routing services, trade as principal in the sponsored ATS, or both. 

d) Broker-Dealer Internalization 

 The other type of undisplayed trading center is a non-ATS broker-dealer that 

internally executes trades, whether as agent or principal. Notably, many broker-dealers 

may submit orders to exchanges or ECNs, which then are included in the consolidated 

quotation data. The internalized executions of broker-dealers, however, primarily reflect 

liquidity that is not included in the consolidated quotation data. There are a large number 

of broker-dealers that execute trades internally in NMS stocks.66

 Broker-dealers that internalize executions generally fall into two categories – 

OTC market makers67 and block positioners.68 Broker-dealers that act as OTC market 

                                                       

63 See, e.g., http://www.liquidnet.com/about/liquidStats.html (average U.S. execution size in July 

2009 was 49,638 shares for manually negotiated trades via Liquidnet’s negotiation product); 

http://www.pipelinetrading.com/AboutPipeline/CompanyInfo.aspx (average trade size of 50,000 

shares in Pipeline). 

64 See, e.g., http://www.nasdaqtrader.com/trader/aspx?id=marketshare (average size of NASDAQ 

matched trades in July 2009 was 228 shares); http://nyxdata.com/nysedata/asp/factbook (NYSE 

Group average trade size in all stocks traded in July 2009 was 267 shares). 

65 Data compiled from Forms ATS submitted to Commission for 3d quarter 2009. 

66 For example, more than 200 publish execution quality statistics under Rule 605 of Regulation 

NMS. 

67 An OTC market maker is defined in Rule 600(b)(52) of Regulation NMS as “any dealer that holds 

itself out as being willing to buy and sell to its customers, or others, in the United States, an NMS 

stock for its own account on a regular or continuous basis otherwise than on a national securities 

exchange in amounts of less than block size.” 
 

Appendix A - 6 

makers and block positioners conduct their business primarily by directly negotiating 

with customers or with other broker-dealers representing customer orders. OTC market 

makers, for example, appear to handle a very large percentage of marketable 

(immediately executable) order flow of individual investors that is routed by retail 

brokerage firms.69

e) Market Linkages 

 In adopting Regulations NMS, the SEC also included an “access” rule that, 

among other things, promotes private linkages among market participants and trading 

venues. In contrast to some markets where trading is concentrated on a single exchange 

or market, because liquidity on the equity markets is dispersed across a large number of 

trading centers of different types, linking the various trading venues is critical to the 

successful operation of the national market system. 

 Rule 611 of Regulation NMS provides protection against trade-throughs.70 A 

trade-through is the execution of a trade at a price inferior to a protected quotation for an 

NMS stock. A protected quotation must be displayed by an automated trading center, 

must be disseminated in the consolidated quotation data, and must be an automated 

quotation that is the best bid or best offer of a national securities exchange or FINRA.71 

Importantly, Rule 611 applies to all trading centers, not just those that display protected 

quotations. Trading center is defined broadly in Rule 600(b)(78) to include, among 

others, all exchanges, all ATSs (including ECNs and dark pools), all OTC market 

makers, and any other broker-dealer that executes orders internally, whether as agent or 

principal. In practice, the national best bid and national best offer (“NBBO”)72 is the best 

bid and best offer from among the protected quotations, i.e., the best bid and best offer of 

all the stock exchanges and FINRA’s ADF.73

                                                                                                                                                                     68 “Block size” is defined in Rule 600(b)(9) of Regulation NMS as an order of at least 10,000 shares 

or for a quantity of stock having a market value of at least $200,000. A block positioner generally 

means any broker-dealer in the business of executing, as principal or agent, block size trades for 

its customers. To facilitate trades, block positioners often commit their own capital to trade as 

principal with at least some part of the customer’s block order. 

69 For example, a 2nd quarter of 2009 review of the order routing disclosures required by Rule 606 of 

Regulation NMS of eight broker-dealers with significant retail customer accounts reveals that 

nearly 100% of their customer market orders are routed to OTC market makers. The review also 

indicates that most of these retail brokers either receive payment for order flow in connection with 

the routing of orders or are affiliated with an OTC market maker that executes the orders. 

70 Rule 611(a)(1) requires all trading centers to establish, maintain, and enforce written policies and 

procedures that are reasonably designed to prevent trade-throughs of protected quotations, subject 

to certain exceptions set forth in Rule 611(b). 

71 FINRA operates the Alternative Display Facility (“ADF”), a display-only facility that permits its 

participants to display quotations and report trades, among other things. 

72 17 CFR 242.600(b)(42). 

73 Technically, the NBBO may include the best bid and best offer of a stock exchange or the ADF 

even if is non-automated (i.e., manual). In practice, however, all such markets are fully automated 

with the exception of NYSE (and NYSE Amex, which operates on the same system as NYSE) for 
 

Appendix A - 7 

 Protection against trade-throughs is an important linkage among trading centers 

because it provides a baseline assurance that: (1) marketable orders will receive at least 

the best displayed price, regardless of the particular trading center that executes the order 

or where the best price is displayed in the national market system; and (2) quotations that 

are displayed at one trading center will not be bypassed by trades with inferior prices at 

any trading center in the national market system. 

 Rule 611 also helps promote linkages among trading centers by encouraging 

them, when they do not have available trading interest at the best price, to route 

marketable orders to a trading center that is displaying the best price. Although Rule 611 

does not directly require such routing services (a trading center can, for example, cancel 

and return an order when it does not have the best price), competitive factors have led 

many trading centers to offer routing services to their customers. With Regulation NMS, 

the SEC adopted a “private linkages” approach that relies exclusively on brokers to 

provide routing services, both among exchanges and between customers and exchanges.74 

Under this approach, market participants obtain access to the various trading centers 

through broker-dealers that are members or subscribers of the particular trading center.75 

Rule 610(a) of Regulation NMS, for example, prohibits an SRO trading facility from 

imposing unfairly discriminatory terms that would prevent or inhibit any person from 

obtaining efficient access through an SRO member to the displayed quotations of the 

SRO trading facility.76

                                                                                                                                                                     which, when it hits a liquidity replenishment point for a given security, its quotation becomes nonfirm and thus is not included in the calculation of the NBBO. 

74 Prior to Rule 611, exchanges routed orders through an inflexible, partially manual system called 

the Intermarket Trading System (“ITS”). See Regulation NMS Release, 70 FR at 37538-37539 

(“Although ITS promotes access among participants that is uniform and free, it also is often slow 

and limited.”). 

75 See Regulation NMS Release, 70 FR at 37540 (“[M]any different private firms have entered the 

business of linking with a wide range of trading centers and then offering their customers access to 

those trading centers through the private firms’ linkages. Competitive forces determine the types 

and costs of these private linkages.”). 

76 In addition, Rule 610(c) limits the fees that a trading center can charge for access to its displayed 

quotations at the best prices. Rule 611(d) requires SROs to establish, maintain, and enforce rules 

that restrict their members from displaying quotations that lock or cross previously displayed 

quotations. 

 Section 6(a)(2) of the Exchange Act requires registered exchanges to allow any qualified and 

registered broker-dealer to become a member of the exchange – a key element in assuring fair 

access to exchange services. In contrast, the access requirements that apply to ATSs are much 

more limited. Regulation ATS includes two distinct types of access requirements: (1) order 

display and execution access in Rule 301(b)(3); and (2) fair access to ATS services in general in 

Rule 301(b)(5). An ATS must meet order display and execution access requirements if it displays 

orders to more than one person in the ATS and exceeds a 5% trading volume threshold. An ATS 

must meet the general fair access requirement if it exceeds a 5% trading volume threshold. If an 

ATS neither displays orders to more than one person in the ATS nor exceeds a 5% trading volume 

threshold, Regulation ATS does not impose access requirements on the ATS. 
 

Appendix A - 8 

 In a dispersed and complex market structure with many different trading centers 

offering a wide spectrum of services, brokers play a significant role in linking trading 

centers together into a unified national market system. Brokers compete to offer the 

sophisticated technology tools that are needed to monitor liquidity at many different 

venues and to implement order routing strategies. To perform this function, brokers may 

monitor the execution of orders at both displayed and undisplayed trading centers to 

assess the availability of undisplayed trading interest. Brokers may, for example, 

construct real-time “heat maps” in an effort to discern and access both displayed and 

undisplayed liquidity at trading centers throughout the national market system. 

 Using their knowledge of available liquidity, many brokers offer smart order 

routing technology to access such liquidity. Many brokers also offer sophisticated 

algorithms that will take the large orders of institutional investors and others, divide a 

large “parent” order into many smaller “child” orders, and route the child orders over 

time to different trading centers in accordance with the particular trading strategy chosen 

by the customer. Such algorithms may be “aggressive,” for example, and seek to take 

liquidity quickly at many different trading centers, or they may be “passive,” and submit 

resting orders at one or more trading centers and await executions at favorable prices. To 

the extent they help customers cope with the dispersal of liquidity among a large number 

of trading centers of different types and achieve the best execution of their customers’ 

orders, the routing services of brokers can contribute to the broader policy goal of 

promoting efficient markets. 

 The linkage function of brokers also is supported by a broker’s legal duty of best 

execution. This duty requires a broker to obtain the most favorable terms reasonably 

available when executing a customer order.77 Of course, this legal duty is not the only 

pressure on brokers to obtain best execution. The existence of strong competitive 

pressure to attract and retain customers encourages brokers to provide high quality 

routing services to their customers.78

f) Professional Liquidity Providers on 

Exchanges and ECNs 

 Liquidity on equities exchanges and ECNs is derived from orders to buy or sell 

securities as well as quotations submitted by members of an exchange that are registered 

as market makers. Professional liquidity providers are proprietary traders in the business 

of providing liquidity to the market, often through the submission of limit orders that rest 

on the electronic order books of exchanges and ECNs.79 They include registered entities, 

                                                       

77 See, e.g., Regulation NMS Release, 70 FR at 37537-37538 (discussion of duty of best execution). 

78 In this regard, Rules 605 and 606 of Regulation NMS are designed to support competition by 

enhancing the transparency of order execution and routing practices. Rule 605 requires market 

centers to publish monthly reports of statistics on their order execution quality. Rule 606 requires 

brokers to publish quarterly reports on their routing practices, including the venues to which they 

route orders for execution. 

79 As noted above, over-the-counter market makers also provide liquidity by trading chiefly with 

customer orders. 
 

Appendix A - 9 

such as exchange specialists and market makers, as well as unregistered proprietary 

trading firms that engage in passive market making and other types of trading strategies. 

As discussed below, some types of professional liquidity providers have certain 

obligations, such as to provide liquidity whether the market is up or down and maintain 

fair and orderly markets. Other professional liquidity providers do not have such 

responsibilities, including some of the high frequency proprietary trading firms that also 

are discussed below. 

(1) Market Makers 

 In general, the rules of national securities exchanges allow a member, on a 

voluntary basis, to register as a market maker on a security-by-security basis and subject 

to certain obligations. While the rules of a national securities exchange may contain 

provisions that provide for market makers, these rules do not require any member to 

register as a market maker.80 Accordingly, an exchange may not have registered market 

makers even though its rulebook provides for them. In addition, the rules of many 

exchanges permit multiple members to register as market makers for the same security. 

 Pursuant to exchange rules, registered market makers are required to engage in a 

course of dealings for their own account to assist in the maintenance, insofar as 

reasonably practicable, of fair and orderly markets. These exchange rules generally 

require a market maker to maintain a continuous two-sided quotation in the security or 

securities for which the member is registered as a market maker. Such rules, however, do 

not generally dictate the prices at which a market maker must quote. For example, when 

a market maker’s liquidity has been exhausted, or if it is unwilling to provide liquidity, it 

may at that time submit what is called a stub quote – for example, an offer to buy a given 

stock at a penny – to comply with its obligation to maintain a continuous two-sided 

quotation.81 Previously, market makers’ quotations were required to be “reasonably 

related to the prevailing market.” In requesting the deletion of this requirement, 

exchanges argued that the market structure had changed since the requirement was 

originally introduced in 1987 and that the requirement was no longer a meaningful means 

of ensuring market execution quality because of the highly competitive and increasingly 

automated environment of equities trading, and also because markets were required to 

abide by the trade-through protections of Regulation NMS.82 In addition, it was believed 

that the duty of best execution would ensure that market makers with the most 

competitive quotations receive executions and thereby provide incentives for them to 

                                                       

80 In addition, the Exchange Act does not require a national securities exchange to have market 

makers. See, e.g., Securities Exchange Act Release Nos. 61698 (March 12, 2010), 75 FR 13151 

(March 18, 2010) (order granting the exchange registration of EDGX Exchange, Inc. and EDGA 

Exchange, Inc.). 

81 See, e.g. Nasdaq Rule 4613; NYSE Arca Equities Rule 7.23; and BATS Rule 11.8. 

82 See Securities Exchange Act Release No. 56586 (October 1, 2007), 72 FR 57085 (October 5, 

2007) (SR-NASDAQ-2007-069). 
 

Appendix A - 10 

quote at or near the NBBO, and that the quality of a market maker’s executions could 

also be reviewed by looking at market execution quality reports.83

 Certain exchanges have a single market maker for each security traded on that 

exchange. In the past, NYSE maintained a “specialist”-based market structure, with the 

specialist serving as the market professional that managed trading in the specific 

securities he was assigned.84 The NYSE specialist was responsible for the execution of 

all orders coming into the Exchange, for conducting auctions on the NYSE floor, and for 

maintaining an orderly market in assigned securities. Specialists’ dealer activities were 

governed, in part, by negative and affirmative trading obligations. Rule 11b-1 under the 

Exchange Act85 requires exchanges that permit members to register as specialists to have 

rules governing specialists’ dealer transactions so that their proprietary trades conform to 

the negative and affirmative obligations. The negative obligation as set forth in Rule 

11b-1 under the Act requires that a specialist’s dealings be restricted, so far as 

practicable, to those reasonably necessary to permit the specialist to maintain a fair and 

orderly market.86 The affirmative obligation as set forth in Rule 11b-1 under the Act 

requires a specialist to engage in a course of dealings for its own account to assist in the 

maintenance, so far as practicable, of a fair and orderly market.87

 In 2008, in order to adapt to the more electronic marketplace and increased 

competition from other trading venues, NYSE replaced its specialist system with a 

system of “Designated Market Makers” (“DMMs”). DMMs are similar to specialists in 

many ways, including in that there is only a single DMM on NYSE for each stock. Some 

obligations, such as the negative obligations specialists were subject to, no longer apply 

to DMMs. In addition, DMMs now have the ability to trade on parity with other market 

participants, as well as functionality reserved solely for DMMs that permits them to 

transmit a schedule setting forth additional liquidity that DMMs commit to provide in 

their assigned securities at specific price points. At the same time, DMMs are subject to 

other responsibilities, some the same as those previously imposed on specialists and 

others new. For example, DMMs are subject to quoting depth guidelines and are 

obligated to maintain a bid or an offer at the NBBO for a certain percentage of the trading 

day. 

(2) High Frequency Traders 

 Highly automated trading systems have helped enable a business model for a new 

type of professional liquidity provider that is distinct from the more traditional exchange 

specialist and over-the-counter (“OTC”) market maker. In particular, proprietary traders 

                                                       

83 Id. 

84 Section 11(b) of the Exchange Act allows the rules of a national securities exchange to permit a 

member to be registered as a specialist and act as both a broker and a dealer. 15 U.S.C. 78k(b). 

85 17 CFR 240.11b-1. 

86 17 CFR 240.11b-1(a)(2)(iii). 

87 17 CFR 240.11b-1(a)(2)(ii). 
 

Appendix A - 11 

now use high speed systems by submitting large numbers of orders that can result in 

more than 1 million trades per day by a single firm. These proprietary traders often are 

labeled as engaging in high-frequency trading (“HFT”), though the term does not have a 

settled definition and may encompass a variety of strategies in addition to passive market 

making. 

 HFT traders can be organized in a variety of ways, including as a proprietary 

trading firm (which may or may not be a registered broker-dealer and member of 

FINRA), as the proprietary trading desk of a multi-service broker-dealer, or as a hedge 

fund (all of which are referred to hereinafter collectively as a “proprietary firm”). Other 

characteristics often attributed to proprietary firms engaged in HFT are: (1) the use of 

extraordinarily high-speed and sophisticated computer programs for generating, routing, 

and executing orders; (2) use of co-location services and individual data feeds offered by 

exchanges and others to minimize network and other types of latencies; (3) very short 

time-frames for establishing and liquidating positions; (4) the submission of numerous 

orders that are cancelled shortly after submission; and (5) ending the trading day in as 

close to a flat position as possible (that is, not carrying significant, unhedged positions 

over-night). Given the competitive pressures to maximize their speed of trading, HFT 

firms typically will attempt to streamline the code for their trading algorithms. However, 

every check and filter in that code reduces its speed, creating a tension. 

 HFT is one of the most significant market structure developments in recent years. 

Estimates of HFT volume in the equity markets vary widely, though they often are 50 

percent of total volume or higher.88 By any measure, HFT is a dominant component of 

the current market structure and is likely to affect nearly all aspects of its performance. 

In addition, though the term HFT implies a large volume of trades, some of the concerns 

that have been raised about particular strategies used by proprietary firms do not 

necessarily involve a large number of trades. Indeed, any particular proprietary firm may 

simultaneously be employing many different strategies, some of which generate a large 

number of trades and some that do not. Conceivably, some of these strategies – for 

example, if they dampen short-term volatility or promote efficient pricing by narrowing 

spreads – may benefit market quality and long-term investors and others could be 

harmful. 

g) Relevant Equity Market Structure Features 

 A number of features relating to the equity markets are relevant to the events of 

May 6, 2010 and are discussed below: 

                                                       

88 See, e.g., Jonathan Spicer and Herbert Lash, Who’s Afraid of High-Frequency Trading?, 

Reuters.com, December 2, 2009 (available at 

http://www.reuters.com/article/idUSN173583920091202) (“High-frequency trading now accounts 

for 60 percent of total U.S. equity volume, and is spreading overseas and into other markets.”); 

Scott Patterson and Geoffrey Rogow, What’s Behind High-Frequency Trading, Wall Street 

Journal, August 1, 2009 (“High frequency trading now accounts for more than half of all stocktrading volume in the U.S.”). 
 

Appendix A - 12 

(1) Order Types 

Market Orders: In certain cases, and particularly for illiquid securities, a large 

order or influx of orders can soak up available liquidity across the market, resulting in an 

order, particularly if it is a market order, breaking through many price levels in an effort 

to obtain an execution at any price. A market order is an order to buy or sell a stock at 

the best available market price. Market orders do not require an execution at a specific 

price or price range. With market orders, the order submitted is generally assured an 

execution; however, there is no limit on what the execution price can be. This contrasts 

with limit orders, which are submitted with a specified limit price. Limit orders guard 

against executions at prices at which the order submitter is not willing to trade, though 

the trade-off is that the order may not be executed if the market suddenly moves away 

from the specified limit price. 

Stop loss market orders are orders that turn into market orders when the stop price 

of the order is reached. When an investor places a stop loss market order to sell, the 

investor is instructing the broker to sell a stock at the market if it falls to a certain price. 

In a normal market, where liquidity exists as the stock price goes up or down, this 

strategy can protect an investor from taking a major loss if the stock drops significantly 

by selling at a predetermined price to minimize the loss. However, during times of 

extreme market volatility, the use of market orders when stop loss levels are triggered 

could result in executions at aberrant prices if all other liquidity has already been 

exhausted. 

 The rules of some exchanges provide a “collar” for market orders. For example, 

on BATS, any portion of a market order that would otherwise execute at a price more 

than $0.50 or 5 percent worse than the NBBO at the time the order initially reaches the 

exchange, whichever is greater, will be cancelled.89 BATS’s market order thresholds are 

intended to help avoid executions on BATS of market orders at prices that are 

significantly worse than the initial NBBO, particularly in thinly-traded securities. BATS 

market participants that intend to trade against liquidity at price points beyond the market 

order thresholds can specify that intent by instead submitting a marketable limit order.90

 Similarly, on NASDAQ, subject to certain exceptions,91 market orders (called 

“Unpriced Orders” on NASDAQ) are “Collared Orders” that, for any portion of a 

Collared Order that would execute at a price more than $0.25 or 5 percent worse than the 

NBBO at the time when the order reaches NASDAQ, whichever is greater, will be 

cancelled. In proposing to adopt its collar for market orders, NASDAQ stated that it was 

intended to reduce the risk that unpriced orders might execute at prices significantly 

                                                       

89 BATS Rule 11.9(a)(2). 

90 See Securities Exchange Act Release No. 34-59258 (January 15, 2009), 74 FR 4788 (January 27, 

2009) (SR-BATS-2009-001). 

91 Unpriced Orders would not be Collared Orders for: (1) Market On Open Orders; (2) Market On 

Close Orders; (3) Unpriced Orders included in a Nasdaq Halt Cross or Nasdaq Imbalance Cross; 

or (4) Unpriced Orders that are Reference Price Cross Orders. See Nasdaq Rule 4751(e)(13). 
 

Appendix A - 13 

worse than the NBBO. Nasdaq noted that market participants generally expect that their 

orders will be executed in full at a price reasonably related to the prevailing market, but 

that participants might not be aware if there is insufficient liquidity at or near the NBBO 

to fill the entire order, particularly for thinly-traded securities.92

Intermarket Sweep Orders: Regulation NMS also introduced the use of 

intermarket sweep orders. An intermarket sweep order is a limit order that meets the 

following requirements: (1) when routed to a trading center, the limit order is identified 

as an intermarket sweep order; and (2) simultaneously with the routing of the limit order 

identified as an intermarket sweep order, one or more additional limit orders, as 

necessary, are routed to execute against the full displayed size of all protected quotations 

with a superior price.93 These additional limit orders must be marked as intermarket 

sweep orders to allow the receiving market center to execute the order immediately 

without regard to better-priced quotations displayed at other trading centers (by 

definition, each of the additional limit orders would meet the requirements for an 

intermarket sweep order). 

 A trading center may immediately execute any order identified as an intermarket 

sweep order.94 It therefore need not delay its execution for the updating of the betterpriced quotations at other trading centers to which orders were routed simultaneously 

with the intermarket sweep order. A trading center itself may also route out intermarket 

sweep orders and thereby clear the way for immediate internal executions at the trading 

center.95

                                                       

92 See Securities Exchange Act Release No. 60371 (July 23, 2009), 74 FR 38075 (July 30, 2009) 

(SR-Nasdaq-2009-070). 

93 Rule 600(b)(3) of Regulation NMS. 17 CFR 242.600(b)(3). 

94 Rule 611(b)(5) of Regulation NMS. 17 CFR 242.611(b)(5). 

95 Rule 611(b)(6) of Regulation NMS. 17 CFR 242.611(b)(6). 

 To illustrate the operation of intermarket sweep orders, assume that a broker-dealer’s customer 

wished to sell a large amount of a stock. Trading Center A is displaying the national best bid of 

500 shares at $10.00, along with quotations in its proprietary depth-of-book data feed of 1500 

shares at $9.99, and 5000 shares at $9.97. The customer decides to sweep all liquidity on Trading 

Center A down to $9.97. Assume also that Trading Center B is displaying a protected bid of 2000 

shares at $9.99, Trading Center C is displaying a protected bid of 400 shares at $9.98, and Trading 

Center D is displaying a protected bid of 200 shares at $9.97. The broker-dealer could execute 

this trade for its customer, subject to its best execution responsibilities, by simultaneously routing 

the following orders: (1) an intermarket sweep order to Trading Center A with a limit price of 

$9.97 and a size of 7000 shares; (2) an intermarket sweep order to Trading Center B with a limit 

price of $9.99 and a size of 2000 shares; and (3) an intermarket sweep order to Trading Center C 

with a limit price of $9.98 and a size of 400 shares. 

All of these orders would meet the requirements of the definition of intermarket sweep orders 

because the necessary orders simultaneously were routed to execute against the displayed size of 

all better-priced protected quotations. Trading Centers A, B, and C all could execute their orders 

immediately without regard to the protected quotations displayed at other trading centers. No 

order would need to be routed to Trading Center D because the price of its bid was not superior to 

the most inferior limit price of the order routed to Trading Center A. Assuming the customer 

obtained a fill for each of its orders at the displayed prices and sizes, it would have been able to 
 

Appendix A - 14 

(2) Temporary Unavailability of Market-Specific 

Liquidity 

Liquidity Replenishment Points: NYSE utilizes a hybrid floor/electronic trading 

model, unlike most other markets today which are fully electronic. In attempting to meld 

the traditional open-outcry floor-based auction model with today’s technology, NYSE’s 

trading system utilizes what are known as “liquidity replenishment points” (“LRPs”).96 

LRPs are best thought of as a “speed bump” and are intended to dampen volatility in a 

given stock by temporarily converting from an automated market to a manual auction 

market when a price movement of sufficient size is reached. In such a case, trading on 

NYSE in that stock will “go slow” and pause for a time period to allow the Designated 

Market Maker to solicit additional liquidity before returning to an automated market. 

This “speed bump” occurs even when there may be additional interest on NYSE’s book 

beyond the LRP price point. 

 LRPs are calculated by NYSE automatically throughout the trading day. 

Specifically, the LRP is calculated upon the opening trade of the day in the security or, if 

there is no opening trade, on the opening quote, and is recalculated (i) every 30 seconds 

thereafter based on the last sale; (ii) after a manual trade by the DMM; (iii) when 

automatic executions resume after an LRP is reached; and (iv) upon the first sale or quote 

after automatic executions resume following an LRP. The precise LRP value varies 

according to the security’s share price and average daily volume within specified ranges. 

LRPs are calculated by adding or subtracting the LRP value to the last sale price or quote 

as appropriate on the exchange in the relevant security.97

 When an incoming order on the NYSE would result in an execution [at or] outside 

an LRP or the stock is quoted outside an LRP, automatic executions in the security are 

suspended on that side of the market. In addition, NYSE will suspend automated 

quotations in the security, and will identify its quote on the consolidated tape with a 

“non-firm” indicator. This is referred to as a “slow market” or “going slow” in the 

security. NYSE will resume automated quotations and automatic executions as soon as 

possible after an LRP is reached, once the DMM manually determines the reopening 

price. In many cases, this occurs in a fraction of a second, but when the market is 

particularly volatile, it can take a minute or more. Upon resumption of automatic 

executions, a new LRP is calculated for the security. On days of major market volatility, 

stocks with significant and continual declines may cause NYSE trading to remain in the 

“go slow” mode for extended periods or to intermittently return to automated execution 

status before quickly again hitting another LRP and thereby “going slow” again. 

                                                                                                                                                                     obtain an immediate execution of a 9400-share trade by sweeping through four price levels at 

Trading Center A, while also honoring the protected quotations at two other trading centers. 

96 For example, if the last sale price in a security is $20 and the LRP value is $0.40, an LRP would 

be reached at $20.40 on the upside or $19.60 on the downside. 

97 NYSE Rule 1000(a)(iv). 
 

Appendix A - 15 

Self-Help: An exchange may exclude the quotations of another exchange from its 

determination of whether the other exchange has a better “protected” price to which it 

must route orders for execution under Regulation NMS if that other exchange is 

experiencing a failure, material delay, or malfunction in its systems or equipment.98 This 

is known as invoking “self-help” against the other exchange.99 This mechanism gives 

trading centers a remedy if another trading center repeatedly fails to provide an 

immediate response (within one second) to incoming orders attempting to access its 

quotes. 

(3) Stub Quotes 

As noted above, in order to comply with their obligation to maintain continuous 

two-sided quotations, market makers are permitted under the rules of certain exchanges 

to utilize stub quotes. When a market order is submitted to an exchange, the order 

immediately will seek the best available liquidity, including the protected quotes of other 

markets, regardless of price. In times of market stress, if the only liquidity available is, 

for example, a one-cent stub quote, the market order, by its terms, will execute against 

the stub quote. 

(4) Clearly Erroneous Executions Rules 

 Erroneous trades can result from a variety of causes, including human error or 

computer malfunction. Because the markets today are increasingly fast, automated, and 

interconnected, an erroneous trade on one market can very rapidly trigger a wave of 

similarly erroneous trades on other markets.100

 The equities exchanges have each adopted “clearly erroneous execution rules” 

that are designed to permit them to break trades that are clearly erroneous. Under these 

rules, which were last revised in late 2009 to make them more consistent across the 

various exchanges, an exchange member may request that an exchange officer review a 

potentially erroneous execution and declare it null and void. Alternatively, an equities 

exchange may review potentially erroneous executions on its own motion. 

 The clearly erroneous execution rules recognize that, in most circumstances, 

trades that are executed between parties should be honored. On rare occasions, however, 

the price of the executed trade indicates a “clearly erroneous error” may exist, suggesting 

                                                       

98 Rule 611(b)(1) of Regulation NMS. 17 CFR 242.611(b)(1). 

99 See Question 4.07 of Responses to Frequently Asked Questions Concerning Rule 611 and Rule 

610 of Regulation NMS, available at http://sec.gov/divisions/marketreg/nmsfaq610-11.htm#sec4

(detailing the elements that must be included in a trading center’s policies and procedures to 

implement the self-help exception). 

100 For example, if the last trade in a stock is $20, and a computer malfunction at one firm causes a 

series of trades to occur on multiple exchanges at prices exceeding $50, the automated systems of 

other firms may quickly follow, with erroneous trades rapidly impacting multiple markets and 

market participants. 
 

Appendix A - 16 

that it is unrealistic to expect that the parties to the trade had come to a meeting of the 

minds regarding the terms of the transaction and that the trade should be broken. 

 In determining whether to break trades, the rules permit equities exchanges to 

consider breaking a trade only if the price exceeds the consolidated last sale price by 

more than a specified percentage amount: 10% for stocks priced under $25; 5% for stocks 

priced between $25 and $50; and 3% for stocks priced over $50. These percentage 

thresholds may be (i) doubled for executions occurring between 9:30 a.m. and 10:00 a.m., 

when the S & P 500 Futures are up or down between 3% and 5% at 9:15 a.m. or (ii) 

tripled when the S & P 500 Futures are up or down 5% or greater at 9:15 a.m. 

 The equities exchanges also may consider additional factors to determine whether 

an execution is clearly erroneous, including but not limited to, system malfunctions or 

disruptions, volume and volatility for the security, news released for the security, whether 

trading in the security was recently halted/resumed, whether the security was subject to a 

corporate action, overall market conditions, consideration of primary market indications, 

and executions inconsistent with the trading pattern in the stock. 

 When an event involves erroneous trades that occur in multiple markets, the rules 

provide that the equities exchanges may use a higher percentage threshold in an effort to 

coordinate a result across markets. Although not required by the rules, the markets 

generally convene conference calls to discuss coordinated action when such events occur. 

Each exchange, however, retains the right to make its own determination on whether to 

nullify trades. 

 Pursuant to exchange rules, a clearly erroneous determination may generally be 

appealed, unless a determination is made that the number of the affected transactions is 

such that immediate finality is necessary to maintain a fair and orderly market and to 

protect investors and the public interest. In addition, the equities markets generally do 

not allow appeals of clearly erroneous rulings that are made in conjunction with other 

market centers. 

 This was the clearly erroneous execution framework in existence on May 6, 2010. 

(5) Short Sales 

Short selling is defined by Rule 200 of Regulation SHO as “any sale of a security 

which the seller does not own or any sale which is consummated by the delivery of a 

security borrowed by, or for the account of, the seller.”101 Short selling often can play an 

important role in the market for a variety of reasons, including contributing to efficient 

price discovery, mitigating market bubbles, increasing market liquidity, promoting capital 

formation, facilitating hedging and other risk management activities, and limiting upward 

                                                       

101 17 CFR 242.200(a). 
 

Appendix A - 17 

market manipulations. There are, however, circumstances in which short selling can be 

used as a tool to manipulate the market.102

Due to its concerns regarding persistent fails to deliver103 and potentially abusive 

“naked” short selling, the SEC adopted Regulation SHO, which became effective in early 

2005.104 As adopted in 2005, this Regulation imposed three general requirements with 

respect to short sales: a marking requirement, a locate requirement and a close-out 

requirement. Since 2005, the SEC has adopted several amendments to Regulation SHO. 

Two of the most recent amendments included further tightening the Regulation’s closeout requirement and adding a short sale price test restriction. 

In connection with further tightening the Regulation’s close-out requirement, in 

the fall of 2008, the SEC adopted temporary Rule 204T of Regulation SHO, with an 

expiration date of July 31, 2009.105 Temporary Rule 204T strengthened the close-out 

requirements of Regulation SHO for fails to deliver resulting from sales of any equity 

security. Prior to the adoption of temporary Rule 204T, Regulation SHO’s close-out 

requirement had applied only to those securities with a persistent and substantial level of 

fails to deliver (known as “threshold securities”). Due to the positive impact that 

temporary Rule 204T, as well as other recent SEC actions, had on reducing fails to 

deliver in equity securities, the SEC made the requirements of temporary Rule 204T 

permanent, with some limited modifications.106

                                                       

102 For example, in 2003, the SEC settled a case against certain parties relating to allegations of 

manipulative short selling in the stock of a corporation. The Commission alleged that the 

defendants profited from engaging in massive “naked” short selling that flooded the market with 

the stock, and depressed its price. See Rhino Advisors, Inc. and Thomas Badian, Lit. Rel. No. 

18003 (Feb. 27, 2003); SEC v. Rhino Advisors, Inc. and Thomas Badian, Civ. Action No. 03 civ 

1310 (RO) (S.D.N.Y); see also U.S. v. Russo, 74 F.3d 1383, 1392 (2d Cir. 1996) (short sales were 

sufficiently connected to the manipulation scheme as to constitute a violation of Exchange Act 

Section 10(b) and Rule 10b-5); S.E.C. v. Gardiner, 48 S.E.C. Docket 811, No. 91 Civ. 2091 

(S.D.N.Y. Mar. 27, 1991) (alleged manipulation by sales representative by directing or inducing 

customers to sell stock short in order to depress its price).

103 A fail to deliver occurs when a seller fails to deliver securities to the buyer when delivery is due. 

104 See Securities Exchange Act Release No. 50103 (July 28, 2004), 69 FR 48008 (August 6, 2004). 

105 See Securities Exchange Act Release No. 58733 (October 14, 2008), 73 FR 61706 (October 17, 

2008); see also Securities Exchange Act Release No. 58572 (September 17, 2008), 73 FR 54875 

(September 23, 2008). 

106 See Securities Exchange Act Release No. 60388 (July 27, 2009), 74 FR 38266 (July 31, 2009). 

Under Rule 204, if a firm that clears and settles trades has a fail to deliver position at a registered 

clearing agency in any equity security for a short sale transaction in that equity security, the firm 

must, by no later than the beginning of regular trading hours on the settlement day following the 

settlement date, referred to as T+4, immediately close out the fail to deliver position by borrowing 

or purchasing securities of like kind and quantity. If the fail to deliver position results from a long 

sale or bona fide market making activity, the firm must, by no later than the beginning of regular 

trading hours on the third settlement day following the settlement date, referred to as T+6, 

immediately close out the fail to deliver position by borrowing or purchasing securities of like 

kind and quantity. If a firm that clears and settles trades does not purchase or borrow shares, as 

applicable, to close out a fail to deliver position in accordance with Rule 204, the firm, and any 

broker-dealer from which it receives trades for clearance and settlement, must borrow or arrange 
 

Appendix A - 18 

With respect to adding a short sale price test restriction, in February 2010, the 

SEC approved Rule 201 of Regulation SHO, which restricts short selling in NMS stocks 

to a price above the national best bid after a stock’s price has declined by 10% or more 

from the prior day’s closing price.107 The Rule became effective on May 10, 2010 and 

has a six month implementation period. Thus, compliance with the Rule was not required 

on May 6, 2010. 

Rule 201 requires a trading center to establish, maintain, and enforce written 

policies and procedures that are reasonably designed to prevent the execution or display 

of a short sale order of an NMS stock at a price that is less than or equal to the current 

national best bid once the circuit breaker has been triggered. The price test restriction, 

once in effect, will apply to all short sales in that stock for the remainder of the day and 

the following day, unless an exception applies. Under the Rule, the listing market for the 

NMS stock must determine whether the stock’s price has decreased by 10% or more from 

its prior day’s closing price. The listing market must then immediately notify the single 

plan processor responsible for consolidating information for the NMS stock that the 

circuit breaker has been triggered. The single plan processor is then required to 

disseminate the information to the markets. 

2. Overview of Listed Options Markets 

A listed option is any option traded on a registered national securities exchange or 

automated facility of a national securities association. To date, all orders in listed options 

are executed only on registered national securities exchanges. The Options Clearing 

Corporation (“OCC”), a clearing agency registered with the SEC, is considered the issuer 

and guarantor of each listed options contract, and all listed options transactions are 

centrally cleared through OCC. 

Listed options are currently traded on eight national securities exchanges, owned 

by six entities. These eight exchanges are BATS, BOX (a facility of BX), CBOE, ISE, 

NASDAQ OMX Phlx, NOM (a facility of Nasdaq), NYSE Amex, and NYSE Arca. 

Based on market share data for April 2010 obtained from the OCC,108 the exchange with 

the highest market share of option volume was CBOE, with 33.88%. The two exchanges 

owned by The NASDAQ OMX Group, Inc. together had a market share of 23.91% 

(NASDAQ OMX Phlx had 21.51% and NOM had 2.40%). The two exchanges owned by 

NYSE Euronext together had a market share of 23.63% (NYSE Arca had 12.98% and 

NYSE Amex had 10.65%). ISE had a market share of 19.17% and BOX had a market 

share of 2.21%. 

                                                                                                                                                                     to borrow securities prior to accepting or effecting further short sales in that security, until the firm 

closes out the fail to deliver position by purchasing securities of like kind and quantity and that 

purchase has cleared and settled at a registered clearing agency. 

107 See Securities Exchange Act Release No. 61595 (February 26, 2010), 75 FR 11232 (March 10, 

2010).

108 See Table 8. 
 

Appendix A - 19 

Similar to NMS stocks, most listed options are traded on multiple exchanges. In 

contrast to some markets where trading is concentrated on a single exchange or market, 

because liquidity on the options markets is dispersed across eight exchanges, linking the 

various exchanges is critical to the successful operation of the national market system for 

listed options. The options exchanges have implemented a joint industry plan to enhance 

the linking of the trading of listed options across the multiple exchanges. Most recently, 

in August 2009, the options exchanges implemented a new plan (the “Options Plan”), 

approved by the SEC,109 which includes a “trade-through” rule that prevents the 

execution of trades on one options exchange at prices lower than a Protected Bid or 

higher than a Protected Offer.110 Each exchange adopted rules to implement the Options 

Plan that prohibit its members from effecting trade-throughs, subject to certain 

enumerated exceptions. The approach to trade-throughs under the Options Plan is similar 

to that taken by the SEC under Rule 611 of Regulation NMS.111

As with NMS stocks, linkage among options exchange is an important protection 

against trade-throughs because it provides a baseline assurance that: (1) marketable 

orders will receive at least the best displayed price, regardless of the particular exchange 

that executes the order or where the best price is displayed in the national market system; 

and (2) quotations that are displayed at one exchange will not be bypassed by trades with 

inferior prices at any other options exchange in the national market system. 

The trade-through prohibition for listed options also helps promote linkages 

among exchanges by encouraging them, when they do not have available trading interest 

at the best price, to route marketable orders to an exchange that is displaying the best 

price. Although the options exchanges are not required to route orders to better prices (an 

exchange can, for example, cancel and return an order when it does not have the best 

price), competitive factors have led options exchanges to offer routing services to their 

customers. Pursuant to the Options Plan, the options exchanges effectively adopted a 

                                                       

109 See Securities Exchange Act Release No. 60405 (July 30, 2009), 74 FR 39362 (August 6, 2009) 

(File No. 4-546). 

110 A “Protected Bid” “Protected Offer” means a bid or offer in an option series that is displayed by 

an Eligible Exchange, is disseminated pursuant to the Options Price Reporting Authority Plan 

(“OPRA Plan”), and is the Best Bid or Best Offer of an Eligible Exchange. A “Best Bid” or “Best 

Offer” means the highest bid price or the lowest offer price communicated by a member of an 

Eligible Exchange to any broker-dealer or to any customer at which such member is willing to buy 

or sell, either as principal or agent. “Eligible Exchange” means a national securities exchange 

registered with the Commission in accordance with Section 6(a) of the Exchange Act that, among 

other things, is a Participant Exchange in OCC and is a party to the OPRA Plan. See Sections 

2(1), 2(2), 2(14), and 2(17) of the Options Plan. 

 The OPRA Plan is a national market system plan approved by the SEC pursuant to Section 11A of 

the Exchange Act and Rule 608 thereunder. See Securities Exchange Act Release No. 17638 

(March 18, 1981), 22 S.E.C. Docket 484 (March 31, 1981). 

111 See supra note 58. 
 

Appendix A - 20 

“private linkage” approach that relies exclusively on brokers to provide routing services 

among exchanges.112

Just like registered exchanges that trade NMS stocks, registered exchanges that 

trade listed options must undertake self-regulatory responsibility for their members and 

file their proposed rule changes for approval with the SEC. These proposed rule changes 

publicly disclose, among other things, the trading services and fees of exchanges. 

The registered exchanges that trade listed options have various market structures. 

Some are fully electronic (such as ISE, BATS, and NOM), while others have hybrid 

models that combine electronic trading with floor trading (such as CBOE, NYSE Amex, 

and NASDAQ OMX Phlx). In addition, some of the options exchanges have in the past 

few years adopted the “maker-taker” pricing model that is prevalent in the markets 

trading NMS stocks. The introduction of the marker-taker model followed the reduction 

of the quoting increment in certain options in 2007.113 Under this model, nonmarketable, resting orders that offer (make) liquidity at a particular price receive a 

liquidity rebate if they are executed, while incoming orders that execute against (take) the 

liquidity of resting orders are charged an access fee. The SEC recently published for 

comment a proposal that would cap the amount of fees an options exchange could charge 

for executions against the best displayed prices of the exchange at $0.30 per contract.114 

Exchanges typically charge a somewhat higher access fee than the amount of their 

liquidity rebates, and retain the difference as compensation. 

Some other options exchanges use a “broker payment” model. These exchanges 

generally charge no or low fees for the execution of customers’ orders,115 but often 

charge other types of fees on a per-transaction basis. For example, most options 

exchanges charge a surcharge or “royalty” fee for executions in certain index option 

classes. Many exchanges also charge a payment for order flow or “marketing” fee to 

market makers that trade with customer orders on the exchange. The exchange then 

                                                       

112 Prior to the Options Plan, the options exchanges routed specific linkage orders through a standalone system, or hub, which acted as a centralized data communications network that 

electronically linked the options exchanges to one another. See Securities Exchange Act Release 

No. 60405, supra note 109. 

113 On January 26, 2007, the then-existing six options exchanges implemented a pilot program to 

quote certain options series in thirteen classes in one-cent increments. Nasdaq became a 

participant in this program on March 31, 2008, when it commenced trading on NOM, and BATS 

became a participant on February 26, 2010 when it commenced trading on BATS Options 

Exchange Market. Since 2007, the pilot program has been extended and expanded several times.

114 See Securities Exchange Act Release No. 61902 (April 14, 2010), 75 FR 20738 (April 20, 2010).

115 Exchanges that use the “broker payment” model also generally give priority to customer orders at 

the best price over other orders or quotations at that price. After customer orders are executed, the 

rules of “broker payment” options exchanges dictate how the remainder of an incoming order is 

allocated against resting non-customer orders or quotations. Exchanges that use a “broker 

payment” model do not give priority to orders from certain customers who are “professional” 

customers under exchange rules. “Professional” customers are treated on ISE, CBOE, NYSE 

Amex and Nasdaq OMX Phlx in the same manner as a broker-dealer for purposes of specified 

order execution rules, including priority rules. 
 

Appendix A - 21 

makes the proceeds from such “marketing” fees available to collectively fund payment 

for order flow to brokers directing order flow to the exchange. 

The registered options exchanges typically offer a wide range of order types for 

trading on their markets. Examples of order types include market orders,116 limit orders, 

and intermarket sweep orders.117 Some of the order types are displayable in full if they 

are not executed immediately. Others are un-displayed, in full or in part. For example, a 

reserve order type will display part of the size of an order at a particular price, while 

holding the balance of the order in reserve and refreshing the displayed size as needed.118 

In general, displayed orders are given execution priority at any given price over fully undisplayed orders and the un-displayed size of reserve orders.119

Unlike with NMS stocks, all listed option orders are executed on registered 

national securities exchanges. Thus, broker-dealers cannot internally execute trades in 

listed options in the over-the-counter market. Instead, all such trades must be sent to a 

registered exchange for execution pursuant to the exchange priority rules. In addition, 

there is one registered ATS that conducts a listed options business. Any orders matched 

by this ATS, however, must be sent to a registered exchange for execution pursuant to the 

exchange’s priority rules. 

As with NMS stocks, in a dispersed and complex market structure with many 

different options exchanges offering a wide spectrum of services, brokers play a 

significant role in linking exchanges together into a unified national market system. 

Brokers compete to offer the sophisticated technology tools that are needed to monitor 

liquidity at many different venues and to implement order routing strategies. To perform 

                                                       

116 See supra section entitled “Order Types.” 

117 See Section 2(9) of the Options Plan. Intermarket sweep orders in the options markets are 

functionally similarly to the ISO order for NMS stocks. See supra notes 93-95 and accompanying 

text. 

118 See, e.g., NYSE Arca Options Rule 6.62 (defining NYSE Arca’s reserve order as a limit order 

with a portion of the size displayed and with a reserve portion of the size that is not displayed on 

NYSE Arca). See also Nasdaq Options Rule Ch. VI. Section 1(e)(6) (defining NOM’s price 

improving order as an order to buy or sell an option at a specified price at an increment smaller 

than the minimum price variation in the security. Price improving orders that are available for 

display shall be displayed at the minimum price variation in that security and shall be rounded up 

for sell orders and rounded down for buy orders); and ISE Rule 715(c) and Supplementary 

Material .02 to ISE Rule 713 (defining ISE’s all-or-none order as a limit or market order that is to 

be executed in its entirety or not at all. These orders are contingency orders and have no priority 

on ISE’s limit order book. Such orders are not displayed in ISE’s best bid or offer but are 

maintained in the system and remain available for execution after all other trading interest at the 

same price has been exhausted).

119 See, e.g., NOM Ch. VI, Section 1(e)(6) (providing that the non-displayed portion of reserve orders 

are not displayed in the system, and have lower priority within the system than an equally priced 

order that is displayed within the system, regardless of time stamp); BATS Rule 21.8(a)(2) 

(generally providing that displayed interest has priority over non-displayed interest at the same 

price); and Supplementary Material .02 to ISE Rule 713 (all-or-none orders are maintained in the 

system and remain available for execution after all other trading interest at the same price has been 

exhausted). 
 

Appendix A - 22 

this function, brokers may monitor the execution of orders at the various exchanges to 

assess the available liquidity. Using their knowledge of available liquidity, brokers can 

offer smart order routing technology to access such liquidity. Many brokers also offer 

sophisticated algorithms that will take the large orders of institutional investors and 

others, divide a large “parent” order into many smaller “child” orders, and route the child 

orders over time to different exchanges in accordance with the particular trading strategy 

chosen by the customer. 

As with NMS stocks, the linkage function of brokers also is supported by a 

broker’s duty of best execution. This duty requires a broker to obtain the most favorable 

terms reasonably available when executing a customer order.120 Of course, this duty is 

not the only pressure on brokers to obtain best execution. The existence of strong 

competitive pressure to attract and retain customers encourages brokers to provide high 

quality routing services to their customers.121

As with the trading of NMS stocks, liquidity on options exchanges is derived 

from orders to buy or sell particular options series as well as quotations submitted by 

members of an exchange that are registered as market makers. Generally, however, 

investors in listed options depend upon the liquidity supplied by professional liquidity 

providers, such as market makers, to a greater extent than in the market for NMS stocks. 

This is due in part to the greater dispersion of trading interest across the thousands of 

series of listed options.122 Professional liquidity providers are proprietary traders in the 

business of providing liquidity to the market, often through the submission of quotations, 

as well as limit orders that rest on the electronic order books of exchanges. They include 

registered entities, such as exchange specialists and market makers, as well as 

unregistered proprietary trading firms that engage in passive market making and other 

types of trading strategies. Some types of professional liquidity providers have certain 

obligations, such as to provide liquidity whether the market is up or down and maintain 

fair and orderly markets. Other professional liquidity providers do not have such 

responsibilities. 

In general, the rules of the options exchanges allow a member, on a voluntary 

basis, to register as a market maker, either on a class-by-class or series-by-series basis. 

Members registered as market makers have certain obligations. Pursuant to the options 

exchanges’ rules, the transactions of a market maker in its market making capacity 

generally must constitute a course of dealings reasonably calculated to contribute to the 

maintenance of a fair and orderly market. These exchange rules also generally require a 

market maker to maintain a continuous two-sided quotation in the options for which the 

member is registered for a specified percentage of the time, or in a specified number of 

                                                       

120 See supra note 77. 

121 Rule 606 of Regulation NMS requires brokers to publish quarterly reports on their routing 

practices, including the venues to which they route options orders for execution. 

122 Options of the same class that have the same standardized terms (e.g., strike price) comprise an 

options series. An options class is an option of the same type (put or call) with the same 

underlying security.
 

Appendix A - 23 

series or classes. For example, the NOM rules require that its market makers maintain a 

two-sided market on a continuous basis in at least 75% of the options series in which they 

are registered. On some options exchanges such rules also limit how wide a market 

maker can quote.123 Other options exchanges, such as NOM, do not have any limitations 

on the price at which market makers can quote. 

While the options exchanges’ rules may contain provisions that provide for 

market makers, these rules do not require any particular member to register as a market 

maker.124 Some exchanges do not trade options on their market unless there is at least 

one market maker registered in the class. At least one options exchange does allow 

options to trade without any market maker registered in the option.125 Accordingly, an 

exchange may not have registered market makers even though its rulebook provides for 

them. In addition, the rules of the options exchanges permit multiple members to register 

as market makers for the same option. Some of the exchanges may have a “lead” or 

“primary” market maker assigned in a given option, while others do not. 

Each options exchange has adopted an “obvious error rule” that is designed to 

permit the exchange to adjust or nullify options transactions that are obviously erroneous. 

An obvious error will be deemed to have occurred when the execution price of a 

transaction differs from the theoretical price126 for the option by an amount equal to at 

least the specified minimum amount indicated in the rule. On some exchanges, an 

obvious error also will be deemed to occur if there are erroneous prints or quotes in the 

underlying, or if there are verifiable systems disruptions or malfunctions. If the options 

exchange determines to adjust the transaction price, the transaction price would be 

adjusted to the theoretical price plus or minus an adjustment penalty that is set forth in the 

rule. A member of an options exchange may request that its options transaction be 

reviewed. Several of the options exchanges also have the discretion to review options 

transactions on their own motion. 

3. Overview of ETFs 

As a general matter, exchange-traded products (“ETPs”) are issuers of exchangetraded securities that give investors exposure to an investment benchmark or strategy. 

ETPs exist in a variety of legal forms, including exchange-traded funds (“ETFs”) 

registered as investment companies under the Investment Company Act of 1940 (“1940 

Act”), exchange-traded notes (“ETNs”), trust-issued receipts, commodity and currency 

                                                       

123 See, e.g., Nasdaq OMX Phlx Rule 1014(c)(i)(A)(1) and (2). 

124 See supra note 80.

125 See Securities Exchange Act Release No. 61735 (March 18, 2010), 75 FR 14227 (March 24, 

2010). 

126 The theoretical price of an option is, for series that are traded on at least one other exchange, the 

last national best bid (for erroneous sell transactions) and the last national best offer price (for) 

erroneous buy transactions) just prior to the trade.
 

Appendix A - 24 

trusts, and commodity pools. All ETPs register offers and sales of shares under the 

Securities Act of 1933 (“Securities Act”), and a national securities exchange lists the 

securities issued by the ETPs for trading on a secondary market. 

An ETF is registered under the 1940 Act as an open-end investment company or a 

unit investment trust (“UIT”). Unlike typical open-end investment companies (“mutual 

funds”) or UITs, ETFs issue and redeem shares only in large aggregations or blocks (such 

as 50,000 ETF shares) commonly called “Creation Units.” Purchase and redemption 

orders for Creation Units are placed by or through participants in the Depository Trust 

Company that have executed a “Participation Agreement” with the distributor of the ETF 

(“Authorized Participants”). Authorized Participants may purchase a Creation Unit with 

a “Portfolio Deposit” equal in value to the aggregate net asset value (“NAV”) of the ETF 

shares in the Creation Unit. The Portfolio Deposit generally consists of a basket of 

securities announced by the ETF’s investment adviser or sponsor at the beginning of each 

business day and usually mirrors the composition of the ETF’s portfolio. Under certain 

circumstances, the Portfolio Deposit may also consist of cash or of cash in lieu of certain 

securities. The value of a Creation Unit could range from hundreds of thousands of 

dollars to several million dollars. After purchasing a Creation Unit, an Authorized 

Participant may hold the ETF shares, or sell ETF shares to other investors. ETF shares 

are not redeemable from the ETF except when aggregated into Creation Units, and then 

only by or through Authorized Participants. Authorized Participants thus act as the 

intermediary between investors and the ETF. 

Like operating companies or closed-end funds, ETFs register offers and sales of 

shares under the Securities Act, and a national securities exchange lists the ETF shares 

for trading. As with any listed security, investors also may trade ETF shares in offexchange transactions. In either case, ETF shares trade at negotiated prices. The 

development of the secondary market in ETF shares depends upon the activities of 

market makers and upon the willingness of Authorized Participants to engage in purchase 

and sale transactions in ETF shares in the secondary market. 

If an Authorized Participant presents a Creation Unit to the ETF for redemption, it 

generally receives a “Redemption Basket” that consists of securities identified by the 

ETF investment adviser or sponsor at the beginning of the day and that usually matches 

the Portfolio Deposit. In some circumstances, the Redemption Basket could also consist 

of cash or of cash in lieu of certain securities. As with purchases from the ETF, 

redemptions from the ETF are priced at NAV. An investor holding fewer ETF shares 

than the amount needed to constitute a Creation Unit may dispose of those ETF shares 

only by selling them in the secondary market at market price, which may be higher or 

lower than the NAV of the ETF shares. The investor also pays customary brokerage 

commissions on sales in the secondary market. 

In the past, ETF shares have not typically traded in the secondary market at a 

significant premium or discount in relation to NAV because of the arbitrage opportunities 

inherent in the ETF structure. Under normal circumstances, if ETF shares begin to trade 

at a discount (i.e., a price less than NAV), arbitrageurs may purchase ETF shares in the 
 

Appendix A - 25 

secondary market and, after accumulating enough shares to equal a Creation Unit, redeem 

them directly from the ETF at NAV if an Authorized Participant, or indirectly through 

that person, thereby acquiring the more valuable securities in the Redemption Basket. In 

purchasing the ETF shares for this purpose, arbitrageurs create greater market demand for 

the shares, which may raise the market price to a level closer to NAV. In contrast, if ETF 

shares trade at a premium (i.e., a price greater than NAV), arbitrageurs may purchase the 

securities in the Portfolio Deposit, use them to obtain the more valuable Creation Units 

from the ETF, and then sell the individual ETF shares in the secondary market to realize 

a profit. As the supply of individual ETF shares available in the secondary market 

increases, the price of the ETF shares may fall to levels closer to NAV. Market makers 

have also been able to maintain efficient markets in ETF shares even in the absence of an 

actual arbitrage transaction by hedging their exposures. 

The 1940 Act does not provide for the ETF structure. Accordingly, ETFs that are 

registered as investment companies under the 1940 Act first must apply to the SEC to 

obtain exemptive relief from certain provisions of the 1940 Act to permit their unique 

operations. The SEC issued the first order to an ETF organized as a UIT in 1992, and 

began issuing orders to ETFs organized as open-end funds in 1996.127 The SEC now has 

issued more than 88 orders to permit ETF operations. As of May 11, 2010, there were 

843 ETFs operating in reliance on these orders with a combined total of approximately 

$740 billion in net assets. 

Unlike ETFs, ETNs are senior, unsecured, unsubordinated debt securities issued 

by banks. ETNs are similar to ETFs in that they offer exchange-traded securities that 

provide investment exposure to certain market benchmarks or strategies. However, 

ETNs do not hold portfolios of securities and are not registered as investment companies 

under the 1940 Act. An investor in an ETN is therefore exposed to the credit risk of the 

issuer. ETNs can be redeemed from the issuer in large blocks of securities such as 

50,000, typically on a weekly basis. There are approximately 90 ETNs. 

Other types of ETPs include trust-issued receipts. Trust-issued receipts represent 

interests in a fixed trust of specified securities. Unlike other types of ETPs, owners of 

trust-issued receipts have the same rights and privileges as if they owned the underlying 

securities beneficially outside of the trust structure, and can receive the reports and 

communications that the issuers of the underlying securities send to their respective 

beneficial owners. ETPs also include commodities and currency trusts, as well as 

commodity pools. While these ETPs trade like ETFs, their portfolios consist of physical 

commodities, currency, or futures, rather than securities, and they are not registered as 

investment companies under the 1940 Act.

                                                       

127 SPDR Trust, Series 1, Investment Company Act Rel. Nos. 18959 (September 17, 1992) (notice) 

and 19055 (October 26, 1992) (order) and The CountryBaskets Index Fund, Inc., Investment 

Company Act Rel. Nos. 21736 (February 6, 1996) (notice) and 21802 (March 5, 1996) (order). 
 

Appendix B - 1 

APPENDIX B 

Overview of the Futures Market Structure 

A futures contract is an agreement to purchase or sell a commodity for delivery in 

the future at a price that is determined when the contract is bought or sold. Each party is 

obligated to fulfill the terms of the contract at the specified price. Futures contracts are 

used to assume or shift price risk, and most positions are satisfied by offset or cash 

settlement, rather than delivery of the underlying commodity or financial instrument. 

 1. Designated Contract Markets 

U.S. futures exchanges (designated by the CFTC as contract markets, as described 

below) are a critical component of the U.S. and world economies, providing significant 

benefits to the public at large as well as market participants.128 Futures markets offer 

individuals and firms in a myriad of industries important vehicles for hedging economic 

risks,129 resulting in more efficient production, lower costs, and other benefits. They also 

provide vital forums for discovering prices.130 For these reasons, futures exchanges are 

affected with a significant national public interest. Further, as self-regulatory 

organizations, futures exchanges must exercise their regulatory authority effectively, 

impartially, and in the public interest. As essential forums for the execution of futures 

transactions and for price discovery, exchanges must ensure fair and financially secure 

trading facilities.131 They must also fulfill self-regulatory responsibilities through 

programs and policies that help ensure market integrity, financial integrity, and the strict 

protection of market participants and the public.132

Futures contracts must be traded on CFTC-regulated exchanges, called 

Designated Contract Markets (DCMs) pursuant to Section 5 of the Commodity Exchange 

Act (CEA).133 DCMs may allow access to their facilities to all types of traders, including 

retail customers. DCMs may list for trading futures or options contracts based on any 

underlying commodity, index, or instrument. To obtain and maintain a designation, a 

DCM must comply with the designation criteria and 18 core principles set forth in 

Sections 5(b) and 5(d) of the CEA and Part 38 of the CFTC’s regulations.134

                                                       

128 Commodity Exchange Act (CEA) Section 3(a), 7 U.S.C. 5(a). 

129 Id.

130 Id.

131 See, e.g., CEA Section 5(b)(3), 7 U.S.C. 7(b)(3); CEA Section 5(b)(5), 7 U.S.C. 7(b)(5). 

132 See, e.g., CEA Section 5(b)(2), 7 U.S.C. 7(b)(2); CEA Section 5(b)(5), 7 U.S.C. 7(b)(5); CEA 

Section 5(d)(4), 7 U.S.C. 7(d)(4); CEA Section 5(d)(11), 7 U.S.C. 7(d)(11); CEA Section 

5(d)(12), 7 U.S.C. 7(d)(12). 

133 CEA Section 5, 7 U.S.C. 7. 

134 CEA Section 5(b), 7 U.S.C. 7(b); CEA Section 5(d), 7 U.S.C. 7(d); 17 CFR 38. 
 

Appendix B - 2 

 The CFTC monitors the discharge of each DCM’s self-regulatory responsibilities 

and ongoing compliance with the CEA and CFTC regulations, including the core 

principles applicable to DCMs, through its program of regular rule enforcement reviews. 

Periodic rule enforcement reviews examine, among other things, a DCM’s audit trail, 

trade practice, disciplinary, and dispute resolution programs. Accurate audit trails are 

essential to reconstruction of trading such as that which occurred on May 6. 

DCMs may implement new rules or rule amendments or list new products by 

filing with the CFTC a certification that the rule or rule amendment complies with the 

CEA and CFTC regulations and policies, or by requesting approval from the CFTC.135

Currently, there are 14 DCMs designated by the CFTC that are actively trading. 

The total trading volume on all of these exchanges combined in 2009 was approximately 

2.7 billion contracts. 

2. Futures Market Structure 

The market structure of U.S. futures markets differs from the market structure of 

U.S. equities markets. In the cash equity markets, the same security may be traded on 

multiple venues that are linked. Under current practice, a given futures contract trades on 

only one exchange. For example, the E-mini S&P 500 futures contract and the S&P 500 

futures contract trade exclusively on the Chicago Mercantile Exchange (CME), and the 

Russell 2000 futures contract trades exclusively on ICE Futures U.S. Futures exchanges 

are not linked in the way securities trading venues are linked. Futures contracts are not 

“issued” by a public company for registration and listing on an exchange. Rather, futures 

exchanges design and list them for trading. 

 The equities and futures markets also differ with respect to clearing. Equities are 

cleared through the National Securities Clearing Corporation. Options on equities are 

cleared through the Options Clearing Corporation. In the futures markets, individual 

exchanges are responsible for maintaining the financial integrity of trading in their listed 

contracts. To fulfill this obligation, exchanges select the clearinghouse(s) that will clear 

and settle their contracts, a clearing model which is also known as “exchange-directed 

clearing.” 

 The CEA requires that all CFTC-regulated DCMs have all DCM-traded contracts 

cleared and settled by a CFTC registered derivatives clearing organization (DCO).136 

One of the critical functions that each DCO performs is the removal of debt obligations 

among clearing members. At a minimum, this is done at the end of the trading session 

for a given trade date.137 This process is accomplished by independently determining a 

                                                       

135 CEA Section 5c(c), 7 U.S.C. 7a-2(c); 17 CFR Part 40. 

136 CEA Section 5(b)(5), 7 U.S.C. 7(b)(5). 

137 The DCO functions as the central counterparty and guarantor for the positions that result from all 

contracts traded on the DCM. This means that the DCO is the long to each short position and the 

short to each long position in all contracts that it clears. DCOs deal exclusively with clearing 

participants. Any market participant that is not a clearing member of a particular DCM must have 
 

Appendix B - 3 

settlement (or marking) price for each contract that is cleared and marking all open 

positions to that price. The DCO collects cash from clearing members that have lost 

money on their positions and pays it to clearing members that have gained money on 

their positions. 

Exchange-directed clearing has been the standard in the futures industry since the 

industry’s inception. The clearinghouse associated with a futures exchange can be either 

vertically integrated into the exchange company itself, or serve as a third-party clearing 

services provider. Historically, most clearinghouses have been integrated into particular 

futures exchanges. The CEA mirrors the exchange-directed clearing model by placing 

upon exchanges the statutory obligation to ensure the financial integrity of their listed 

contracts.138

3. Equity Futures Products 

a. Broad-Based Index Futures139

Stock index futures are financial instruments whereby traders buy or sell a 

standardized value of a stock index for settlement on a future date at a specified price. 

The fundamental economic purpose of stock index futures is to provide a risk 

management tool for financial institutions and other market participants active in the 

stock market. They are widely used by mutual funds, pension funds, endowments, 

foundations and other entities holding securities, as an effective way to protect against 

adverse price movements associated with holding stock portfolios by selling futures or as 

a way to efficiently manage the purchase and sale of stocks as portfolios are balanced or 

adjusted. 

Stock index futures are cash settled and do not provide for delivery of the shares 

underlying the indices. For most stock index futures contracts, contract expiration is on 

the third Friday of the contract month. All open contracts are then settled in cash, based 

on the Special Opening Quotation price for the relevant index on the expiration day.140 

Each futures exchange establishes a contract size by specifying a multiplier. For 

example, with respect to the CME E-mini S&P 500 contract, the contract size is set at 

$50 times the S&P 500 Index value, equal to a notional value of $55,000 per contract 

when the index is at 1,100. Stock index futures are subject to price limits and circuit 

breaker trading halts that are coordinated with trading in the underlying securities 

markets (circuit breakers are discussed in more detail below). Trading and open interest 

                                                                                                                                                                     its positions carried by a clearing member. The DCO for CME is the CME Clearing House, while 

the DCO for ICE Futures US is ICE CLEAR US. 

138 See CEA Section 5(b)(5), 7. U.S.C. 7(b)(5); CEA Section 5(d)(11), 7 U.S.C 7(d)(11). 

139 A broad-based security index means a group or index of securities that does not constitute a 

narrow-based security index. 17 CFR 41.1(c). 

140 The “Special Opening Quotation” is calculated using normal index calculation procedures except 

that the values for the respective components are taken as the actual opening values for each of the 

component equities.
 

Appendix B - 4 

in stock index futures is concentrated in the nearby month, which typically accounts for 

over 90 percent of total activity in all months combined. 

 

Two DCMs, CME and ICE Futures U.S., trade broad-based equity index futures, 

the CME and ICE Futures U.S. The combined total trading volume of all equity index 

products traded at CME and ICE in 2009 was approximately 766 million contracts. 

Stock index futures contracts were introduced in the early 1980’s, beginning with 

the Kansas City Board of Trade’s Value Line Average futures contract and the CME’s 

S&P 500 index futures contract. The CME and other futures markets have listed for 

trading futures on various broad market sector indices. These include the CME Nasdaq 

100, S&P MidCap 400, and S&P Small Cap 600 index futures, the Chicago Board of 

Trade (“CBOT”) Dow Jones Industrial Average Index future and the ICE Futures US 

Russell 2,000 index future. In addition, the CME and other exchanges list options on 

certain stock index futures contracts, including the CME E-mini S&P 500. 

As noted, the CME first launched an S&P 500 futures contract in the early 1980s; 

that contract continues to trade today. That contract, however, has a larger contract size, 

$250 times the level of the S&P 500, compared to the $50 multiplier for the E-mini S&P 

500 contract. The original S&P 500 contract is traded via open outcry during the day 

trading session and on CME Globex during overnight electronic trading hours, while the 

E-mini S&P 500 contract is traded exclusively on Globex. From Monday through 

Thursday, the E-mini S&P 500 contract trades from 4:30 to 5:30 p.m. and from 6:00 p.m. 

to 4:15 p.m. the following day. (It therefore trades until 4:15 p.m. on Friday.) It also 

trades from 6:00 p.m. Sunday through 4:15 p.m. Monday. Open outcry trading in the 

original S&P 500 contract, which takes place from 9:30 a.m. through 4:15 p.m. Monday 

through Friday, overlaps with electronic trading in the E-mini S&P 500 during those 

hours. Electronic trading in the original S&P 500 contract (which as noted above takes 

place only outside of its open outcry trading hours) also overlaps with the E-mini S&P 

500 contract during overnight hours. 

The E-mini S&P 500 contract was launched in 1997, as a smaller contract size 

version of the original S&P 500 futures contract. Since that time, trading volume and 

open interest in the E-mini version has grown dramatically such that, today, the E-mini 

S&P 500 contract is the most actively traded domestic stock index futures contract.141

 Both the E-mini S&P 500 and the pit-traded S&P 500 futures contracts exhibit 

substantial trading volume and open interest. In April 2010, trading in the E-mini S&P 

500 and the pit-traded S&P 500 futures contracts accounted for about 78 percent of the 

total trading volume and about 80 percent of total open interest of all domestic stock 

index futures contracts. For this same period, the E-mini S&P 500 contract alone 

accounted for about 77 percent of total US stock index futures and options activity. In 

this regard, in April 2010, the average daily trading volume in the E-mini S&P 500 

                                                       

141 Total trading volume in the E-mini S&P 500 contract exceeded that of the pit-traded contract in 

2006. In 2006, total trading volume in the E-mini S&P 500 contract was 257,926,680 contracts 

compared to 74,221,810 E-mini equivalent contracts for the pit-traded S&P 500 contract. 
 

Appendix B - 5 

contract was about 2.1 million contracts, compared to about 17,000 contracts for the S&P 

500 contract. As of the close on May 5, total open interest in the E-mini S&P 500 

contract was about 2.6 million contracts (representing a notional value of about $152.4 

billion), compared to about 328,000 contracts for the S&P 500 contract. The $152.4 

billion notional value of the E-mini S&P 500 contract, however, represents only about 

one percent of the $14.1 trillion notional value of the entire U.S. stock market, as 

represented by the Russell 3000 index. 

The Russell 2000 Index Mini futures contract trades on ICE Futures U.S. It was 

originally listed in October 2001 on the CME but moved to ICE Futures U.S. in 

September 2008. April 2010 average daily volume for the contract was 150,885. Open 

interest as of May 5, 2010 was 392,394 representing 10% of total U.S. stock index 

futures open interest. 

b. Security Futures 

The term “security futures product” (SFP) encompasses security futures and 

options on security futures. Security futures includes both futures on a single security 

(called single stock futures) and futures on narrow-based security indices. 

The Commodity Futures Modernization Act of 2000 (CFMA) lifted the ban on 

trading of futures contracts based on single stocks. A security future is a contract for the 

sale or future delivery of a single security or of a narrow-based security index.142 

Previously, these products were prohibited from being offered in the United States. With 

the passage of the CFMA, broad-based security index futures, which are not considered 

security futures products, continue to trade under the sole jurisdiction of the CFTC, while 

security futures products are subject to the joint jurisdiction of the CFTC and the SEC.143

Contract markets that have been designated by the CFTC may trade security 

futures products if they notice register with the SEC and comply with certain 

requirements of the Securities Exchange Act of 1934.144 Likewise, national securities 

exchanges and national securities associations registered with the SEC may trade security 

futures products if they notice register with the CFTC and comply with certain 

requirements of the CEA.145

Only one DCM trades single stock and narrow based index futures contracts, 

OneChicago, which was designated as a contract market by the CFTC in 2002. At 

expiration of a single stock futures contract, the contract is settled by delivery of shares of 

the underlying stock. OneChicago lists 1,936 futures products, of which 233 are futures 

                                                       

142 CEA Section 1a(31), 7 U.S.C. 1a(31); 17 CFR Part 41. 

143 CEA Section 2(a)(1)(C), 7 U.S.C. 2(a)(1)(C); CEA Section 2(a)(1)(D), 7 U.S.C. 2(a)(1)(D). 

144 CEA Section 5f, 7 U.S.C. 7b-1. See also, 17 CFR Part 41. 

145 15 U.S.C. 78f(g)(2). 
 

Appendix B - 6 

on Exchange Traded Funds. The total trading volume on OneChicago in 2009 was 

approximately 3 million contracts. 

4. Electronic Trading 

a. History of Electronic Futures Trading 

Electronic futures trading began at both CME and CBOT in 1992. Over the 

almost two decades since then, electronic trading has come to be the prevalent form of 

trading in U.S. futures markets. Electronic trading volume surpassed open outcry trading 

volume at CBOT in 2004, at CME in 2005, and at the New York Mercantile Exchange 

(NYMEX) in 2007. As of the end of April 2010, electronic trading accounted for 

approximately 88 percent of the combined volume of all CME Group exchanges146—

which collectively account for approximately 97 percent of all U.S. futures and options 

volume—while open outcry trading had declined to approximately 12 percent of the 

combined volume of those exchanges.147 For example, in 2009, total trading volume for 

the S&P 500 futures contract was approximately 10.4 million contracts as compared to 

approximately 556 million contracts for the E-mini S&P 500 contract. 

 The IntercontinentalExchange, Inc. was launched as a fully electronic trading 

venue in 2000. It acquired the former New York Board of Trade, now ICE Futures U.S., 

whose markets traded only by open outcry, in 2006. ICE launched electronic trading at 

ICE Futures U.S. in 2007, and by the end of 2007 all futures contracts there were 

exclusively traded electronically, with only options on futures still traded by open outcry. 

b. Electronic Trading Platforms 

 Equity index futures on U.S. futures exchanges are traded on two electronic 

trading systems, CME Group’s Globex system and the IntercontinentalExchange, Inc.’s 

ICE Trading System. 

 CME Globex supports electronic trading at all CME Group exchanges. The CME 

Globex system also supports the electronic trading of partner exchanges including the 

Kansas City Board of Trade, Minneapolis Grain Exchange, Dubai Mercantile Exchange, 

BM&F Bovespa, and Korea Exchange. Launched in 1992, CME Globex is now accessed 

by customers in more than 85 countries and foreign territories, and is available for trading 

nearly 24 hours a day from Sunday evening to Friday afternoon. In the first quarter of 

2010, CME Globex processed an average daily volume of approximately 9.5 million 

contracts for CME, CBOT, NYMEX and COMEX products. 

                                                       

146 The CME Group exchanges include CME, CBOT, NYMEX, and the Commodity Exchange, Inc. 

(COMEX). 

147 Although all U.S. futures markets trade either exclusively on electronic trading systems or utilize a 

combination of floor trading and electronic trading, this discussion focuses solely on CME Globex 

and ICE Trading System, the systems used to trade the E-mini S&P 500 and the Russell 2000 

equity index futures contracts. 
 

Appendix B - 7 

 The IntercontinentalExchange, Inc.’s ICE Trading System supports electronic 

trading at all ICE futures exchanges, including ICE Futures U.S. (regulated by the 

CFTC), ICE Europe (regulated by the United Kingdom’s Financial Services Authority), 

and ICE Canada (regulated by Canada’s Manitoba Securities Commission). It also 

supports electronic trading for ICE’s OTC swaps markets in oil, electricity, and natural 

gas. It is accessed by customers in 50 countries and is available for trading for about 23 

hours a day from Sunday evening through Friday afternoon. During April 2010, the ICE 

Trading System processed an average daily volume of about 428,000 contracts for ICE 

Futures U.S., and an overall combined average daily volume of almost 1.4 million 

contracts for all trading on the system. 

5. Order Display and System Speed 

CME’s Globex system displays bid and offer prices and volume 10-deep in the 

order book for the E-mini S&P 500 contract, and the ICE Trading System displays the 

full depth of all bids and offers in the order book for all futures contracts traded on ICE 

Futures U.S. At both exchanges, traders can use front-end systems as an interface to 

enter their orders into the respective electronic trading system.148 CME and ICE offer a 

range of different connectivity options to market participants. Market participants’ 

decisions related to application design, network infrastructure, hardware and 

configuration affect how a participant accesses the market.

 Once an order message is received by the Globex matching engine, the system 

affixes a time stamp to the order message and transmits it back to the end-user 

acknowledging the time of receipt at the matching engine. In the E-mini S&P 500 market 

on May 6, the average latency at the matching engine level during the period from 2:30 

p.m. -3:00 p.m. was 3 milliseconds. The average latency during this period for market 

data updates to the last best price and 10-deep book was 1.5 milliseconds. Similarly, 

once an order message is received by the ICE Trading System’s matching engine, the 

system affixes a time stamp to the order message and transmits it back to the end-user 

acknowledging the time of receipt at the matching engine. In the Russell 2000 market on 

May 6, the average latency at the matching engine level during the period from 2:30 p.m. 

-3:00 p.m. was 250 microseconds. The average latency during this period for market data 

updates to the last best price and full order book depth was 250 microseconds. 

During the period from 2:30 p.m. to 3:00 p.m. on May 6 in the June E-mini S&P 

500 index futures contract, the average number of trades per second was approximately 

106 trades, and the average volume per second was approximately 600 contracts. The 

peak number of trades per second occurred at 1:43:21 p.m. with 889 trades. The peak 

volume in one second occurred at 2:46:51 p.m., with 4,456 contracts traded. In 

comparison, on May 13, the Thursday following May 6, the peak message volume in the 

                                                       

148 “Front-end system” refers generally to the technology and infrastructure by which a trader 

interacts with an exchange’s electronic trading system. Front-end systems provide the immediate 

interface through which orders are entered for transmission to the exchange, and through which 

market data is received by the trader. Front-end systems can be proprietary to the trader, furnished 

by third-party providers, or even provided by the exchange itself. 
 

Appendix B - 8 

E-mini S&P 500 occurred between 9:30 a.m. - 10:00 a.m. The average volume per 

second was 133 contracts and the peak volume per second was 2,806 contracts. The 

average number of trades per second was 39 and the peak number of trades per second 

was 891 trades. 

During the period from 2:30 to 3:00 p.m. on May 6 in the Russell 2000 index 

futures contract, the average number of trades per second was 32 trades, and the average 

volume per second was 44 contracts. The peak number of trades per second occurred at 

2:41:41 p.m. with 320 trades. The peak volume in one second occurred at 2:41:44 p.m. 

with 431 contracts traded. For comparison, during the period of 2:30 p.m. -3:00 p.m. on 

May 13, the average volume per second was 11 contracts and the peak volume per second 

was 194 contracts. The average number of trades per second was 7.7 trades and the peak 

number of trades per second was 126 trades. 

6. Co-location 

A driving force behind the growth of electronic trading in the futures industry has 

been the continuing evolution of technologies for generating and executing orders. These 

technologies have improved the speed, capacity, and sophistication of trading functions 

that are available to market participants. 

Many trading firms have trading strategies that are highly dependent upon speed 

in a number of areas: speed of market data delivery from exchange servers to the firms’ 

servers; speed of processing of firms’ trading engines; speed of access to exchange 

servers by firms’ servers; and, speed of order execution and response by exchanges. For 

some trading firms, speed is now measured in microseconds, and any latency or delay in 

order arrival or execution can adversely affect their trading strategy. These trading firms 

are typically referred to as “high frequency” and/or “algorithmic” traders. High 

frequency traders are professional traders that use computer systems to engage in 

strategies that generate a large number of trades on a daily basis. Competition among 

high frequency traders has led to extensive use of co-location and/or proximity hosting 

services.149

Co-location and proximity services refer to trading market and/or certain thirdparty facility space that is made available to market participants for the purpose of 

locating their network and computing hardware closer to the trading market’s matching 

engine. Along with space, co-location and proximity hosting services usually involve 

providing various levels of power, telecommunications, and other ancillary products and 

services necessary to maintain the trading firms’ trading systems. 

                                                       

149 Other characteristics of high frequency trading may also include: (1) the use of computer systems 

to generate, route and execute orders, (2) short time-frames for establishing and liquidating 

positions, (3) submission of numerous orders that are cancelled shortly thereafter, and/or (4) 

ending the trading day in a neutral overall position. 
 

Appendix B - 9 

7. Futures Market Participants 

 As shown in the CFTC’s Commitments of Traders (COT) reports, almost all of 

the participants in equity index futures markets are reportable traders on whom the CFTC 

regularly collects substantial information.150 The vast majority of these traders are 

classified as “commercial traders”151 For example, in the E-mini S&P 500 futures 

market, approximately 90 percent of all traders are reportable, and 70 percent are 

classified as commercial traders. The commercial category includes institutional 

investors such as pension funds, endowments, corporations, insurance companies, brokerdealers, large U.S. and non-U.S. commercial banks, and swaps dealers. 

 The remaining traders include hedge funds and other managed funds, as well as 

day traders. Day traders typically are in and out of the market rapidly, and usually do not 

maintain significant open interest from one trading day to the next, or even one hour to 

the next, although they may represent a significant portion of daily volume. A new type 

of futures market day trader, high frequency traders (described above), employ computer 

trading algorithms to spot market trends that signal when to enter and exit a market, and 

to execute their trading strategies. High frequency traders typically place large numbers 

of orders for small-quantities of contracts, either within a single market or across many 

different markets. 

8. Order Entry 

 Participants in equity index futures markets place orders in a variety of ways. 

Some use the traditional method of telephoning an order to an exchange member firm, 

which takes the order and transmits it either to an electronic trading system or to an 

exchange floor.152 The majority of participants, however, transmit their orders 

                                                       

150 The COT reports provide a breakdown of each Tuesday’s open interest for futures markets in 

which 20 or more traders hold positions equal to or above the reporting levels established by the 

CFTC. The information is available on the CFTC Website, cftc.gov.

151 When an individual reportable trader is identified to the CFTC, the trader is classified either as 

“commercial” or “non-commercial.” All of a trader’s reported futures positions in a commodity 

are classified as commercial if the trader uses futures contracts in that particular commodity for 

hedging as defined in CFTC Regulation 1.3(z), 17 CFR 1.3(z). A trading entity generally gets 

classified as a “commercial” trader by filing a statement with the CFTC, on CFTC Form 40: 

Statement of Reporting Trader, that it is commercially “...engaged in business activities hedged by 

the use of the futures or option markets.” To ensure that traders are classified with accuracy and 

consistency, CFTC staff may exercise judgment in re-classifying a trader if it has additional 

information about the trader’s use of the markets. A trader may be classified as a commercial 

trader in some commodities and as a non-commercial trader in other commodities. A single 

trading entity cannot be classified as both a commercial and non-commercial trader in the same 

commodity. Nonetheless, a multi-functional organization that has more than one trading entity 

may have each trading entity classified separately in a commodity. For example, a financial 

organization trading in financial futures may have a banking entity whose positions are classified 

as commercial and have a separate money-management entity whose positions are classified as 

noncommercial.

152 In the case of the open outcry S&P 500 futures contract, the member firm will transmit the order 

to CME’s trading floor. 
 

Appendix B - 10 

electronically themselves. Many of these orders are first transmitted to the exchange 

clearing member firm that guarantees that participant’s trades, and then to the trading 

system. Some participants who have been approved by their clearing members and the 

exchange can transmit their orders directly to the trading system. 

 In 2008, CME implemented “Globex Credit Controls,” a risk management 

system that enables intermediaries to set credit limits for each customer placing orders 

directly to Globex. While these risk limits are set by the intermediary firm, they are 

applied on an automated basis by the electronic trading system as a backstop to the firm’s 

own risk management architecture. In April 2010, CME promulgated its Rule 949 and 

Advisory 10-153, which specifically require members to make use of these controls. 

Starting at the beginning of 2011, CME will be reviewing member firms’ use of these 

controls (e.g., the reasonableness of the size of the limits) in light of the firms’ financial 

resources. 

ICE has an integrated pre-trade risk management system within the ICE Trading 

System to allow futures commission merchants to set credit limits for each customer 

placing orders into the system. Once set by the FCM, the limits are automatically applied 

to the user by the ICE Trading System. Modifications to the credit limits take effect in 

real-time in the trading system and can be made via the ICE website 24 hours a day, 7 

days a week. These credit settings can be used as the primary risk management tool for 

firms or as a backstop to the firm’s own risk management architecture. All participants 

who trade ICE U.S. Futures’ contracts must utilize these controls to trade on the ICE 

trading system. 

9. Market Making in Futures Markets 

 Futures exchanges are not required to have market makers. However, a futures 

exchange may enter into agreements with an exchange member calling for the member to 

act as a market maker on a specific product or products, in order to provide liquidity for 

new product or in low volume contracts.153 Market maker agreements provide the market 

maker with certain incentives if the market maker, trading for its own account, complies 

with the particular obligations. These market maker agreements generally specify 

volume requirements and impose an affirmative duty on the market maker to make a 

continuous, two-sided market within some specified bid-ask spread in order to receive the 

incentives.154 The requirement that the market maker provide its quotes in a particular 

bid-ask spread means that any quotes the market maker provides to qualify for the market 

maker program must be within a certain range of the then current market price. 

                                                       

153 In the case of CME, it has market maker programs in the following equity index contracts: E-mini 

S&P MidCap 400 Futures, E-mini S&P MidCap 600 Futures, S&P 500 Technology Index Futures, 

S&P 500 Financial Sector Index Futures, E-mini MSCI EAFE Futures, E-mini MSCI Emerging 

Markets Index Futures, and E-mini Dow Futures (European Hours). 

154 Futures exchanges must also make the terms and conditions of market maker programs publically 

available. See, Designation Criteria 7, CEA Section 5(b)(7), 7 U.S.C. 7(b)(7); Core Principle 7, 

CEA Section 5(d)(7), 7 U.S.C. 7(d)(7). 
 

Appendix B - 11 

Market maker programs must comply with applicable core principles and 

designation criteria set out in the CEA,155 and prior to its implementation, a program’s 

criteria must be submitted to the CFTC, either by self-certification or for approval.156 In 

reviewing market maker programs, the CFTC considers, among other things, whether 

market maker incentives would encourage wash or fictitious trading or other trading 

abuses. The CFTC also examines whether the exchange has adequate regulatory 

compliance mechanisms in place to detect trade practice abuses by market maker 

program participants. 

10. Existing Mechanisms to Promote Orderly Markets and Customer 

Protection 

 Both CME Globex and the ICE Trading System have automatic safety features—

termed “pre-trade risk management functionality”—to protect against errors in the entry 

of orders (such as “fat finger” errors), extreme price swings, and erroneous prices. As 

discussed below, these features help ensure fair and orderly markets. 

 First, CME Globex and the ICE Trading System both automatically reject orders 

priced outside a range of reasonability, also known as a “price band.”157 For instance, on 

the E-mini S&P 500 futures contract, the price band is 12 points (approximately one 

percent) above and 12 points below the last executed trade.158 This prevents clearly 

erroneous orders from entering the trading system and helps to prevent “fat finger” errors. 

 Second, both CME and ICE have maximum order size limitations that prevent 

entry into the trading system of an order that exceeds a maximum quantity established by 

the exchange. In the E-mini contract, for example, the maximum quantity is 2,000 

contracts. This protection also helps to prevent “fat finger” errors. With the S&P 500 

Index at 1,100 points as it was on May 6, two thousand E-mini contracts would have a 

notional value of $110 million. The average transaction size in the E-mini contract, 

however, tends to be six contracts, or $330,000. 

                                                       

155 Market maker programs must comply, for example, with Core Principle 2—Compliance with 

Rules (monitor for trade practice abuses), Core Principle 9—Execution of Transactions (ensuring 

that the market remains open, competitive and efficient), Core Principle 12—Protection of Market 

Participants (fiduciary obligations to customers), and Core Principle 18—Antitrust Considerations, 

as well as Designation Criteria 3—Fair and Equitable Trading. See generally, CEA Section 5(b), 

7 U.S.C. 7(b) and CEA Section 5(d), 7 U.S.C. 7(d). 

156 CEA Section 5c(c), 7 U.S.C. 7a-2(c). See also, 17 CFR 40.5; 17 CFR 40.6. 

157 The electronic trading functionality involved is known as “price banding functionality.” 

Generally, the price band is calculated dynamically by the system, based on the last traded price or 

the best bid or offer, and the price band thus moves dynamically with the market price, with its 

outer parameters remaining a fixed distance in points (12 in the case of the E-mini) above and 

below the market price. A “point” on a broad-based equity index, such as the S&P 500, is a 

concept used to measure the collective value of the securities included in the index. 

158 At CME and ICE Futures US, the number of points involved in the price band is set separately by 

each exchange for the products they trade. 
 

Appendix B - 12 

 Third, both CME Globex and the ICE Trading System have protections with 

regard to “stop loss” orders.159 Such orders are triggered if the market declines to a level 

pre-selected by the person entering the order. CME and ICE rules provide that when the 

market declines to the trader’s pre-selected stop level for such an order, the order 

becomes a limit order executable only down to a price within the range of reasonability 

permitted by the system, instead of becoming a market order.160 Requiring that stop 

orders have a limit avoids the possibility that such stop orders could be executed no 

matter how low the market goes. This requirement for all stop orders to convert to limit 

orders prevents, for example, any stop orders from being posted or executed at a price 

unreasonably below the market. 

 Fourth, CME Globex has “Stop Logic” functionality that protects against 

cascading stop orders—the domino effect of one stop order triggering others.161 

Globex’s Stop Logic functionality pauses trading—the pause is termed “the Stop Logic 

reserve period”—when the trading engine recognizes that it has a series of resting stop 

orders that could lead to a cascade and move the market up or down beyond a specified 

amount. The length of the Stop Logic reserve period varies by product and time of day. 

For the E-mini S&P 500, the period is 5 seconds from 9:30 a.m. to 4:15 p.m. and 10 

seconds during the balance of the trading session. The pause allows new orders to enter 

the system to restore liquidity and balance to the order book.162

11. Trade Cancellation 

 Trade cancellation policies balance the adverse effects on market integrity of 

executing trades and publishing trade information inconsistent with prevailing market 

conditions. The intent is to preserve legitimate expectations that executed transactions 

will not be cancelled. 

 At CME, a “no-bust range” is established for each product traded electronically 

on CME Globex. Trade prices within the no-bust range—six points above or below the 

                                                       

159 In the futures markets, however, a stop order as a limit order in the CME Globex and ICE systems. 

As a limit order, a trade cannot be executed at a price below its limit price. 

160 At CME, a market participant entering a stop loss order can pre-select a limit price only within a 

12-point range of reasonability below the stop price. If the participant did not pre-select a limit 

price, the system defaults to a limit price three points below the stop price. At ICE, the participant 

can pre-select a limit price only within four points below the stop price, and the system defaults to 

a limit price four points below the stop price if no limit price is pre-selected. 

161 Absent this Stop Logic functionality, all stop orders at a particular price point would be triggered 

and traded on a first-in, first-out basis; additional resting stops would be triggered and traded as 

the market declined, and new orders would continue to be accepted and traded. While the 

protected range would still be operable, it would continuously adjust downwards with the market 

until a new equilibrium was reached, including, potentially, the execution of all resting stop orders 

in the order book. 

162 Globex’s Stop Logic functionality was originally developed to address thin markets in back 

contract months at times of night when open outcry markets were closed. However, it has played 

a role in volatile markets, such as the May 6 E-mini S&P 500 futures market. 
 

Appendix B - 13 

market price in the case of the E-mini S&P 500 contract—will not generally be busted or 

adjusted. The only exception to this rule is if the Globex Control Center (GCC) 

determines that not busting or adjusting a trade within the no-bust range will have a 

material, adverse effect on the market.163 Exchange rules state that the GCC can adjust 

trade prices or bust trades when such action is necessary to mitigate market disrupting 

events caused by the improper or erroneous use of the electronic trading system or by 

system defects. The GCC may review a trade based on its analysis of market conditions 

or on a request for review by a Globex user. A request for review must be made as soon 

as possible, but will generally not be considered if more than eight minutes have passed 

since the trade occurred. On May 6, CME received no requests to cancel any trades in 

the E-mini S&P 500 futures market, and CME did not cancel any trades. 

 ICE Futures U.S. has established a “No Cancellation Range” (“NCR”) for each 

ICE Futures U.S. product traded on its electronic platform. The NCR for the Russell 

2000 Index Mini futures contract is 400 index points above or below the current anchor 

price (the anchor price is generally the last traded price). Trades within the NCR are not, 

under most circumstances, cancelled, whether as the result of error or otherwise. Traders 

generally have 5 minutes from the time of executing a trade in which to notify ICE 

Futures U.S. of an alleged error trade. ICE generally decides whether an alleged error 

trade will stand or be cancelled within 15 minutes after the time the alleged error trade 

occurred. On May 6, ICE received no requests to cancel any trades in the Russell 2000 

contract, and did not cancel any trades. 

12. Internalization of Orders by Futures Commission Merchants 

 In futures markets, FCMs can match orders in two limited ways. Such orders can 

be matched as a block trade or as an exchange of physicals for related positions 

transaction (“EFRP”), with the permission of customers.164 However, all such 

transactions must be reported to the exchange promptly, and are included in the 

exchange’s audit trail and in market data the exchange subsequently transmits to market 

participants. If a block trade or EFRP is not executed, the FCM can match orders only if 

it follows strict exchange rules governing cross-trades, which require that, before the 

FCM can match such orders, they must be exposed to the market for a certain period of 

time during which they are visible to and available for matching by any market 

                                                       

163 The GCC is the Market Operations and Customer Service desk for electronic trading on the 

Globex System. The GCC handles inquiries, issues, and support requests for the Globex platform, 

including electronic trading, order routing and market data interfaces, and network connectivity.

164 Exchange of Futures for Related Positions includes, among other things. Exchange for Physicals 

(“EFP”), Exchange of Futures for Swaps (“EFS”), and Exchange of Futures for Risk (“EFR”). An 

EFP is a transaction in which the buyer of a cash commodity transfers to the seller a corresponding 

amount of long futures contracts, or receives from the seller a corresponding amount of short 

futures, at a price difference manually agreed upon. An EFS is a privately negotiated transaction 

in which a position in a physical delivery futures contract is exchanged for a cash-settled swap 

position in the same or a related commodity, pursuant to the rules of a futures exchange. An EFR 

is an exchange of futures for, or in connection with, over-the-counter derivative transactions. 
 

Appendix B - 14 

participant. Both the orders and any resulting permissible cross-trade are included in the 

exchange’s market data transmitted to market participants, as well as in the exchange’s 

audit trail. This differs from the situation in equities markets, where orders internalized 

by broker-dealers may not be included in consolidated quotation data visible to the entire 

market. 

13. Sources of Regulatory Data 

 The CFTC’s primary mission is fostering markets that accurately reflect the 

forces of supply and demand for the underlying commodity and are free of abusive 

trading practices. In this capacity, the CFTC conducts oversight of trade execution 

facilities through its market surveillance and market compliance programs. 

 The surveillance program identifies situations that could pose a threat of 

manipulation and to initiate appropriate preventive actions. Each day, for all active 

futures and option contract markets, CFTC staff monitors the daily activities of large 

traders, key price relationships, and relevant supply and demand factors in a continuous 

review for potential market problems. Surveillance is not conducted exclusively at the 

CFTC, surveillance issues are usually handled jointly by the CFTC and the appropriate 

futures exchange. Relevant surveillance information is shared and corrective actions are 

taken, when appropriate. Potential problem situations are jointly monitored and, if 

necessary, verbal contacts are made with the participants in question. These contacts 

may be for the purpose of understanding their trading, confirming reported positions, 

alerting the brokers or traders as to the regulatory concern for the situation, or warning 

them to trade responsibly. If an exchange fails to take actions that the CFTC deems 

appropriate, the CFTC has broad emergency powers under which it can order the 

exchange to take actions specified by the CFTC. 

 The CFTC’s surveillance program uses many sources of market information to 

accomplish its objectives. Some of this information is publicly available, including data 

on the overall supply, demand, and marketing of the underlying commodity; futures, 

option, and cash prices; and trading volume and open interest data. Other information is 

highly confidential under statutory requirements, including data which identifies the 

activity or positions of individual traders. 

 Exchanges report the daily positions and transactions of each clearing member to 

the CFTC. The data are transmitted electronically during the morning after the “as of” 

date. They show, separately for proprietary and customer accounts, the aggregate 

position and trading volume of each clearing member in each futures and option contract. 

The data are used to identify the clearing firms that clear the largest buy or sell volumes 

or hold the biggest positions in a particular market. 

 The clearing member data do not identify the beneficial owners of the positions. 

Information on beneficial owners, however, is provided through the CFTC’s large trader 

reporting system (“LTRS”). Under the CFTC’s LTRS, clearing members, FCMs, and 

foreign brokers (collectively called reporting firms) file daily reports with the CFTC 
 

Appendix B - 15 

pursuant to Part 17 of the CFTC’s regulations, 17 CFR Part 17. As is the case with 

clearing member data, the data are transmitted electronically during the morning after the 

“as of” date. The reports show futures and option positions of traders with positions at or 

above specific reporting levels as set by the CFTC. Current reporting levels are found in 

CFTC Regulation 15.03(b), 17 CFR 15.03(b).165

 If, at the daily market close, a reporting firm has a trader with a position at or 

above the CFTC’s reporting level in any single futures or option expiration month, the 

firm reports that trader’s entire position in all futures and options expiration months in 

that commodity, regardless of size. The CFTC uses addition information obtained from 

the reporting firms—i.e., CFTC Form 102: Identification of “Special Accounts”—and 

traders themselves— i.e., Form 40 “Statement of Reporting Trader”—to aggregate 

positions of a trader that may exist across multiple accounts or firms. 

 The CFTC also collects trade data on a daily, transaction date + 1 (“T+1”), basis 

from all U.S. futures exchanges through “Trade Capture Reports.” Trade Capture Reports 

contain trade and related order information for every matched trade facilitated by an 

exchange, whether executed via open outcry or electronically, or non-competitively (e.g., 

block trades, exchange for physical, etc.). Among the data included in the Trade Capture 

Report are trade date, product, contract month, trade execution time, price, quantity, trade 

type (e.g., open outcry outright future, electronic outright option, give-up, spread, block, 

etc.), trader ID, order entry operator ID, clearing member, opposite broker and opposite 

clearing member, order entry date, order entry time, order number, customer type 

indicator, trading account numbers, and numerous other data points. Additional 

information is also required for options on futures, including put/call indicators and strike 

price, as well as for give-ups, spreads, and other special trade types. 

 All transactional data is received overnight, loaded in the CFTC’s databases, and 

processed by specialized software applications that detect patterns of potentially abusive 

trades or otherwise raise concern. Alerts are available to staff the following morning for 

more detailed and individualized analysis using additional tools and resources for data 

mining, research, and investigation. 

 Time and sales quotes for pit and electronic transactions are also received from 

the exchanges daily. CFTC staff is able to access the market quotes to validate alerts as 

well as reconstruct markets for the time periods in question. Currently, staff is working 

with exchanges to receive all order book information in addition to the executed order 

information already provided in the Trade Capture Report. This project is expected to be 

completed within the next year; at present such data remains available to staff through 

“special calls” (described below) requesting exchange data. 

 In addition to information received daily, the CFTC may also obtain information 

through what is referred to as a Special Call. Under CFTC Regulation 18.05, every trader 

                                                       

165 The current reporting levels, in number of contracts, for securities products are as follows: S&P 

500 Index, 1,000; Other Broad-Based Securities Indices, 200; Individual Equity Securities, 1,000; 

and Narrow-Based Security Indices, 200. 
 

Appendix B - 16 

who holds or controls a reportable futures or option position is required to keep books 

and records showing details concerning all positions and transactions in the commodity, 

as well as details concerning all positions and transactions in the cash commodity, and all 

commercial activity that the trader hedges in the futures or option contract in which the 

trader is reportable.166 Such information must be made available to the CFTC upon 

request. A current use of the special call provision is in the capture of relevant 

information of index activity in commodity markets. To obtain the necessary data on 

OTC swap agreements, CFTC staff issued a special call to financial firms to receive data 

about the index activity of a variety of investors. 

                                                       

166 17 CFR 18.05. 
 

Appendix C - 1 

APPENDIX C 

Cross-Market Circuit Breakers 

Circuit breakers are coordinated, cross-market trading halts that were designed to 

operate during significant market declines and to substitute orderly, pre-planned halts for 

the ad hoc trading halts which can occur when market liquidity is exhausted. Circuit 

breakers also provide opportunities for markets and market participants to assess market 

conditions and potential systemic stress during a historic market decline. The U.S. 

securities and futures markets adopted circuit breaker procedures in October 1988 in 

response to their experiences during the historic market declines of October 1987 and to 

recommendations contained in studies of the pricing and liquidity problems that arose 

during the sharp price swings and volume surges on October 20, 1987, that came close to 

shutting down the markets. 

In addition, futures exchanges have “price limits” for stock index futures 

contracts.167 These price limits were also adopted in response to the historic market 

declines in October 1987. A price limit, in itself, does not halt trading in the futures, but 

prohibits trading at prices below (and sometimes above) the pre-set limit based on the 

previous session’s settlement price. Intra-day price limits are removed at pre-set times 

during the trading session, such as 10-minutes after the futures are determined to be 

“locked limit” down (up).168 Daily price limits remain in effect for the entire trading 

session. Specific price limits are set for each stock index futures contract. 

1. Cross-Market Circuit Breaker Halts 

a. The October 1987 Market Break and the Adoption of 

Circuit Breakers in 1988 

In October 1987, the U.S. securities markets experienced an extraordinary surge 

in price volatility and trading volumes (“October 1987 Market Break”). On Monday, 

October 19, the DJIA declined 508 points, representing a record one-day decline of 

almost 23%. On October 20, the DJIA again declined sharply before share prices 

stabilized. The combination of historic price swings and unprecedented trading volumes 

overwhelmed the operational capacities and liquidity of the securities and futures 

markets. By mid-day on October 20, heavy selling pressure had produced large order 

imbalances and numerous ad hoc trading halts in individual stocks. Liquidity and pricing 

difficulties also resulted in uncoordinated mid-day trading suspensions on major options 

                                                       

167 While price limits are common in futures contracts, there are no price limits for stocks, equity 

options or index options. 

168 A futures contract is found to be “locked limit” if exchange officials determine that prices are 

consistently at the limit price. A price decline that touches a limit but quickly bounces back will 

not trigger a “locked limit” determination. 
 

Appendix C - 2 

exchanges and several large stock index futures exchanges. While the subsequent rally in 

market prices in the afternoon averted more widespread financial problems, the near 

shutdown of the markets on October 20 became a central focus of several studies of the 

October 1987 Market Break and resulted in the adoption of circuit breaker procedures in 

1988. 

Immediately following the October 1987 Market Break, the Presidential Task 

Force on Market Mechanisms was established with Nicholas F. Brady as Chairman. The 

report issued by the Task Force on January 8, 1988 (“Brady Report”) recommended a 

number of initiatives to address future periods of extreme market volatility, including the 

implementation of circuit breaker mechanisms coordinated across the markets for stocks, 

options, and stock index futures. The Brady Report noted that the market disorders of 

October 1987 “became, in effect, ad hoc circuit breakers, reflecting the natural limits to 

market liquidity.” Accordingly, the Brady Report maintained that the October 1987 

Market Break “demonstrates that it is far better to design and implement coherent, 

coordinated circuit breaker mechanisms in advance, than to be left at the mercy of the 

unavoidable circuit breakers of chaos and system failure.”169 

After the issuance of the Brady Report, the President’s Working Group on 

Financial Markets (“Working Group”) was formed with the mandate to determine the 

extent to which coordinated regulatory action was necessary to strengthen the nation’s 

financial markets.170 The May 1988 Interim Report (“Interim Report”) of the Working 

Group recommended a number of initiatives to assist the markets in coping with future 

periods of extraordinary price swings and volume surges, including the adoption of 

circuit breakers that would provide coordinated trading halts and reopenings for large, 

rapid market declines that threaten to create panic conditions.171 The Working Group 

recommended that all U.S. markets for stocks, options, and futures halt trading for one 

hour if the DJIA declined 250 points from its previous day’s closing level and halt 

trading for two hours if the DJIA declined 400 points from its previous day’s closing 

level.172 In addition, the Working Group anticipated quarterly reviews of the circuit 

breaker thresholds to determine whether changes in index levels necessitated changes to 

the triggers so that they continue to reflect percentage declines approximately equivalent 

to 12% and 20%.173

Partly in response to the October 1987 Market Break and the recommendations of 

the Brady Report and the Working Group, the securities and stock index futures markets 

submitted proposals to the SEC and CFTC in 1988 to implement circuit breakers that 

would impose temporary trading halts following significant market declines. The circuit 

                                                       

169 See Report of the Presidential Task Force on Market Mechanisms (January 1988) at 66. 

170 The Working Group, established in March 1988, consists of the Secretary of the Treasury and the 

Chairmen of the SEC, CFTC, and the Board of Governors of the Federal Reserve System. 

171 See Interim Report of the Working Group on Financial Markets (May 1988) at 5. 

172 See Interim Report at 4. 

173 See Interim Report at Appendix A. 
 

Appendix C - 3 

breaker rules for the securities and stock index futures markets were implemented in 

October 1988.174

The circuit breakers approved in 1988 provided for a one-hour trading halt in all 

securities markets if the DJIA declined 250 points from its previous day’s closing level 

and for a subsequent two-hour trading halt if the DJIA declined 400 points from its 

previous day’s close. In approving the original circuit breakers, the SEC and CFTC 

noted that the circuit breakers were not an attempt to prevent markets from reaching new 

price levels, but an effort by the securities and futures markets to arrive at a coordinated 

means to address potentially destabilizing market volatility along the lines of the historic 

decline of the October 1987 Market Break.175 The SEC and CFTC also believed that 

circuit breakers would help promote stability in the equity and equity-related markets by 

providing for increased information flows and enhanced opportunity to assess 

information during times of extreme market movements. The SEC and CFTC believed 

that circuit breakers could provide market participants with an opportunity to re-establish 

an equilibrium between buying and selling interest and ensure that market participants 

had a reasonable opportunity to become aware of and respond to a dramatic market 

decline.176

a) Modifications to the Circuit Breakers from 1996 to 1998 

The SEC and CFTC approved several modifications to the markets’ circuit 

breaker rules starting in 1996. In July 1996, the agencies approved rule modifications to 

reduce the length of the trading halts by half. In addition, when the SEC and CFTC 

approved a six-month extension of the circuit breakers in October 1996,177 the agencies 

urged the markets to reach a consensus on the size of increases in the trigger levels 

required to ensure that cross-market trading halts would be imposed only during market 

declines of historic proportions.178 In response to the agencies’ recommendations, the 

markets submitted proposals to increase the circuit breaker triggers to levels of 350 and 

550 points in the DJIA.179 In approving the 350/550 trigger levels through January 31, 

1998, the agencies stated that the new trigger levels represented a substantial 

improvement over the existing 250/400 trigger levels. Nevertheless, the agencies noted 

                                                       

174 See Securities Exchange Act Release Nos. 26198 (Oct. 19, 1988), 53 FR 41637 (October 24, 

1988) (Amex, CBOE, NASD, and NYSE) (“1988 Approval Order”); 26218 (October 26, 1988), 

53 FR 44137 (Nov. 1, 1988) (CHX); 26357 (December 14, 1988), 53 FR 51182 (December 20, 

1988) (BSE); 26368 (December 16, 1988), 53 FR 51942 (Dec. 23, 1988) (PSE); 26386 (December 

22, 1988), 53 FR 52904 (December 29, 1988) (PHLX); and 26440 (January 10, 1989), 54 FR 1830 

(January 17, 1989) (CSE). 

175 Id. 

176 Id. 

177 See Securities Exchange Act Release No. 37890 (October 29, 1996), 61 FR 56983 (November 5, 

1996) (Amex, NYSE, and PHLX). 

178 Id. 

179 See Securities Exchange Act Release No. 38221 (January 31, 1997) 62 FR 5871 (NYSE, Amex, 

CBOE, CHX, BSE, and PHLX) (“1997 Approval Order”). 
 

Appendix C - 4 

that trigger levels should be amended to reflect an extraordinary decline under prevailing 

market conditions and that the SEC and CFTC would work with the markets to develop 

procedures for reevaluating the circuit breaker triggers on at least an annual basis.180

On October 27, 1997, the nation’s securities markets fell by a then-record 

absolute amount, with the DJIA declining 554.26 points (7.18 percent) to close at 

7161.15. This was first and only day that the cross-market trading halt circuit breaker 

procedures were implemented. At 2:36 p.m., the DJIA had declined 350 points, thereby 

triggering a 30-minute halt on the stock, options, and index futures markets. After 

trading resumed at 3:06 p.m., prices fell rapidly to reach the 550-point circuit breaker 

level at 3:30 p.m., thereby ending the trading session 30 minutes prior to the normal stock 

market close. 

Immediately following the events of October 27, the markets and regulators began 

considering further revisions to the circuit breaker procedures. There was general 

consensus that the 7 percent decline in the DJIA on October 27 did not justify the early 

closure of the markets on that day. Accordingly, an agreement was reached by the 

markets and the agencies that trigger points for circuit breaker halts should be increased 

substantially and measures should be taken to permit normal market closings if circuit 

breaker thresholds were reached late in a trading session. 

Accordingly, the SEC and the CFTC approved revised circuit breaker rules for the 

markets in April 1998.181 The revised rules established trading halts following one-day 

declines in the DJIA of 10 percent, 20 percent, and 30 percent. The NYSE would 

calculate the trigger levels at the beginning of each calendar quarter, using the average 

closing value of the DJIA for the previous month to establish specific point values for the 

quarter. Trading would halt for one hour if the DJIA declined 10 percent prior to 2:00 

p.m., and for one-half hour if the DJIA declined 10 percent between 2:00 p.m. and 2:30 

p.m. If the DJIA declined by 10 percent at or after 2:30 p.m., trading would not halt at 

the 10 percent level. If the DJIA declined 20 percent prior to 1:00 p.m., trading would 

halt for two hours; trading would halt for one hour if the DJIA declined 20 percent 

between 1:00 p.m. and 2:00 p.m., and trading would halt for the remainder of the day if a 

20 percent decline occurred at or after 2:00 p.m. If the DJIA declined 30 percent at any 

time, trading would halt for the remainder of the day. 

 These were the circuit breaker levels in place on May 6, 2010.182

                                                       

180 Id. 

181 See Securities Exchange Act Release No. 39846 (April 9, 1998), 63 FR 18477 (April 15, 1998) 

(NYSE, Amex, BSE, CHX, NASD, and PHLX) (“April 1998 Approval Order”). 

182 In November, 2002, trading in security futures products (SFPs) began. Any NYSE-declared 

circuit breaker trading halts would apply also to DCMs that trade SFPs including single security 

and narrow-based security index futures.
 

Appendix C - 5 

2. CME Price Limit “Speed Bumps” 

In response to the historic market volatility in October 1987, the CME adopted 

downside intra-day price limits for index futures even before the cross-market circuit 

breaker trading halts were established. The CME’s 1988 price limits were set at 5 

percent, 10 percent, and 15 percent, as well as a daily limit at 20 percent. These were not 

coordinated with the circuit breakers or any stock exchange rules and were based on the 

price of the index futures contract from the previous day’s settlement price. For each of 

the intra-day price limits, trading would be subject to the price limit for 10 minutes after a 

“locked limit” finding by exchange officials. If the futures contract were limit offered at 

the end of that 10-minute period, then trading would halt for two minutes, after which the 

next price limit would be in effect. The daily price limit of 20 percent would remain in 

effect for the remainder of the trading session. 

The futures price limits also have changed since their adoption in 1988. The 

CME eliminated the 5 percent and 15 percent intra-day price limits effective on January 

1, 2008 in order to harmonize rules across CME and CBOT contracts. The CME and ICE 

10 percent and 20 percent intra-day price limits act as “speed bumps” - once a stock 

index futures contract is determined to be locked limit, the limit remains in effect and/or 

halts for a period of time determined by the exchange, after which, the next price limit 

becomes effective. The daily price limit of 20% was replaced by a new limit of 30%. 

The CME also currently maintains a 5% price limit above or below the regular 

trading hour closing level applicable to overnight electronic trading only. No trading 

may occur at a price more than 5% above or below the regular trading hours closing 

level. If the price limit is bid or offered at the limit within five minutes prior to the 

opening of regular trading hours, then trading will be halted for the remainder of 

electronic trading hours until the commencement of regular trading hours at 9:30 a.m. 

During the trading halt, the CME will provide an indicative opening price for the reopening of regular trading hours. 

These were the index futures price limits in place on May 6, 2010. 

A review of the history of price limit declarations shows that the 5 percent price 

limit was hit for the S&P 500 and E-mini S&P 500 futures contracts only 5 times since 

1988.183 At no time during that period were any higher level price limits hit. However, 

over the period 1998 through 2007, when the 5 percent price limit was in effect, there 

was a total of six days when the E-mini S&P 500 futures contract fell by 5% or more 

during the trading day. This discrepancy could be explained by method used to calculate 

the 5 percent price limit, which is reset each calendar quarter based on the average 

settlement price over the prior calendar month. After the CME eliminated the 5 percent 

limit, the E-mini S&P 500 fell by more than 5% on 21 days.

                                                       

183 The S&P 500 5 percent price limit was hit on October 8, 1988, October 13, 1989, October 27, 

1997, April 4, 2000, and April 14, 2000. 
 CONFIDENTIAL – DRAFT 

 5-18 5:30AM 

Appendix D - 1 

APPENDIX D 

Futures Market Information 

A. Most Active U.S. Stock Index Futures 

B. List of Active Designated Contract Markets 

C. Detailed Trading Statistics for the E-mini S&P 500 June 2010 futures on May 6, 

2010. Volume, Price, Account, User Summary by hour, minute and second 
 

Appendix D - 2 

A. MOST ACTIVE U.S. STOCK INDEX FUTURES

Name Multiplier Index 

Close 

5/6/10 

Notional 

Value at 

close 

Open 

Interest 

as of 

close on 

5/6/10 

Notional Futures 

on Close on 

5/5/10 

Market 

Share of 

US Stock 

Index 

futures 

(Notional 

futures) 

Volume on 

5/6/10 

(30-day avg. 

vol.) 

1 CME E-MINI 

S&P 500 

$50 x 

Index 

1,128 $56,400 2,719,296 $152,482,722,429 48.97% 5,682,565 

(2,482,578) 

2 CME S&P 

500 STOCK 

INDEX 

$250 x 

Index 

1,128 $281,250 333,153 $95,546,157,913 30.69% 54,701 

(72,622) 

3 ICE US 

RUSSELL 

2000 MINI 

INDEX 

FUTURE 

$100 x 

Index 

672 $67,200 399,159 $27,419,678,895 8.81% 392,565 

(171,686) 

4 CME 

NASDAQ-100 

STOCK 

INDEX 

(MINI) 

$20 x 

Index 

1,893 $37,860 381,569 $15,439,860,428 4.96% 736,784 

(320,934) 

5 CME 

NASDAQ-100 

STOCK 

INDEX 

$100 x 

Index 

1,893 $189,300 26,667 $4,882,124,351 1.57% 4,302 

(1,823) 

6 CME E-MINI 

S&P 400 

STOCK 

INDEX 

$100 x 

Index 

776 $77,600 97,062 $7,841,925,535 2.52% 56,629 

(29,161) 

7 CME S&P 

400 MIDCAP 

STOCK IDX 

$500 x 

Index 

776 $388,000 1,788 $720,427,400 0.23% 115 

(61) 

8 CBT DOW 

JONES 

INDUSTRIAL 

AVG- x $5 

$5 x 

Index 

10,520 $52,600 84,706 $4,557,248,441 1.46% 326, 704 

(145,245) 
 

Appendix D - 3 

9 CBT DOW 

JONES 

INDUSTRIAL 

AVG x $10 

$10 x 

Index 

10,520 $105,200 11,045 $1,190,212,740 0.38% 894 

(720) 

10 CBT DOW 

JONES 

INDUSTRIAL 

AVG x $25 

$25 x 

Index 

10,520 $263,000 28 $7,311,500 0.00% 10 

(5) 

11 ICUS 

RUSSEL 1000 

MINI INDEX 

FUTURE 

 $100 x 

Index 

621 $62,100 19,589 $1,250,936,760 0.40% 1842 

(918) 

12 CME E-MINI 

S&P 

SMALLCAP 

600 INDEX 

$100 x 

Index 

360 $36,000 689 $23,348,990 0.01% 392 

(141) 
 

Appendix D - 4 

B. DCMS WITH CONTRACTS THAT ACTIVELY TRADE

1. CBOE Futures Exchange. An electronic exchange operating in Chicago, IL; CBOE 

Futures lists contracts on various volatility measures; CBOE Futures is a subsidiary of the 

Chicago Board of Options Exchange (designated on August 7, 2003). 

2. CBOT. CBOT (Board of Trade of the City of Chicago, Inc.) is located in Chicago, IL; 

Trading takes place both electronically on CME Globex and on trading floors; CBOT 

listed contracts include agricultural, indexes, interest rates, and treasuries; originally 

organized as a grain cash market in 1848, and became a subsidiary of the CME Group, 

Inc. in 2007. 

3. CCFE. An electronic exchange located in Chicago, IL; CCFE (Chicago Climate Futures 

Exchange, LLC) is a wholly owned subsidiary of the Chicago Climate Exchange Inc. 

(CCX); CCFE listed contracts include emissions contracts (designated November 9, 

2004). 

4. CME. CME (Chicago Mercantile Exchange Inc.) is located in Chicago, IL; trading takes 

place both electronically on CME Globex and on trading floors; CME listed contracts 

include agricultural, weather, FX, indexes, and real estate; began operation in 1898; the 

parent of CME (CME Group, Inc.) purchased CBOT in 2007. 

5. COMEX. COMEX (The Commodity Exchange, Inc) is located in New York, NY; 

trading take place electronically on CME Globex and on trading floors in New York; 

COMEX lists contracts on precious metals; COMEX became a subsidiary of the New 

York Mercantile Exchange in 1994. 

6. ELX. An electronic exchange located in New York, NY; ELX (ELX Futures, L.P.) was 

founded by a consortium of dealers, trading firms, and technology providers, including a 

number of large commercial and investment banks; ELX currently lists only treasury 

contracts. (designated May 22, 2009). 

 

7. ICE US. ICE U.S. (ICE Futures US, Inc) is located in New York, NY; trading takes 

place both electronically on the ICE Trading system and on trading floors in New York; 

ICE US listed contracts include currencies, iron ore, agricultural products, and the 

Russell 1000 stock index. NYBOT was created by the merger of the Coffee, Sugar and 

Cocoa Exchange and the New York Cotton Exchange in 2004; NYBOT changed its name 

to ICE Futures US, Inc. after it became a wholly-owned subsidiary of the 

IntercontinentalExchange in 2007. 

8. KCBT. KCBT (Kansas City Board of Trade) is located in Kansas City, KS; trading takes 

place both electronically on CME Globex and on trading floors in Kansas City; listed 

contracts include wheat and a broad-based stock index; KCBT futures trading in grains 

began in 1876. 

 

9. MGEX. MGEX (Minneapolis Grain Exchange) is located in Minneapolis, MN; trading 

takes place both electronically on CME Globex and on trading floors; listed contracts 
 

Appendix D - 5 

include wheat and agricultural indexes; MGEX was started in 1881 and renamed MGEX 

in 1947. 

10. NFX. NFX (NASDAQ OMX Futures Exchange) is an electronic exchange in New York, 

NY; primarily lists currency and currency-related contracts. NFX was started as 

Philadelphia Board of Trade; its parent (then PHLX) was bought by NASDAQ OMX in 

2008. 

11. NYMEX. NYMEX (New York Mercantile Exchange) is located in New York, NY; 

trading takes place both electronically on CME Globex and on trading floors in New 

York; listed contracts include energy-related and, emissions. NYMEX was originally 

founded in 1872 as the Butter and Cheese Exchange of New York (which became 

NYMEX in 1882) and became a wholly-owned subsidiary of CME Group Inc. in 2008. 

12. NADEX. NADEX (North American Derivatives Exchange, Inc.) is a Chicago-based, 

electronic exchange offering retail-oriented, binary and variable payout options on stock 

indices, foreign exchange rates, economic events, metals, and certain agricultural 

commodities (designated February 18, 2004). 

13. NYSE Liffe. NYSE Liffe (NYSE Liffe U.S. LLC) is an electronic exchange located in 

New York, NY; listed contracts include precious metals and equity indexes; NYSE Liffe 

was launched in 2008 as a subsidiary of NYSE Euronext (designated August 21, 2008). 

14. OneChicago. OneChicago (OneChicago LLC Futures Exchange; also called OCX) is an 

electronic exchange located in Chicago, IL; listed contracts include individual stocks, 

narrow-based indexes, and exchange traded funds. OneChicago is owned by a consortium 

that includes Interactive Brokers Group, LLC, the CME Group, Inc., and the CBOE 

(designated June 11, 2002). 
 

Appendix D - 6 

C. Detailed Trading Statistics for the e-Mini S&P 500 June 

2010 futures

This section contains detailed trading data for the CME e-mini S&P 500 June 2010 

futures contract covering the following three time periods (all times Eastern Daylight 

Time): 

• Activity by hour from May 5 4:00 PM through May 6 5:00 PM 

• Activity by minute from May 6 1:00 PM through May 6 4:15 PM 

• Activity by second from May 6 2:41:00 PM through May 6 2:50:00 PM 

 For each time slice, the following information is displayed: 

• The number of trades (Trades) 

• The number of individual contracts traded (Volume) 

• The price of the first trade (First) 

• The highest trade price (High) 

• The lowest trade price (Low) 

• The price of the last trade (Last) 

• The difference between the last price and the first price (Last – First Range) 

• The difference between the highest price and the lowest price (High/Low Range) 

• The volume weighted average price (VWAP) 

• The number of unique Globex accounts executing buys (Buy Accts) 

• The number of unique Globex accounts executing sells (Sell Accts) 

• The number of unique parties executing buys (Buy User IDs)184

• The number of unique parties executing sells (Sell User IDs) 

• A graphical display of the volume (Volume Graph) 

As can be seen in the tables, the number of User IDs is normally greater than the number 

of Accounts. This can be due to the use of a single account by multiple User IDs. For 

example, there is not a specific limit to the number of automated trading systems (ATS) 

that an individual can use to trade his personal account. Each ATS would be given a 

unique User ID. 

                                                       

184 CME Group Rule 576 requires that each order entered into CME Globex include the submission of an 

operator ID, also referred to as the “Tag 50 ID” or “User ID”, which is unique to the party who entered the 

order. For orders entered manually, the Tag 50 ID must be unique to the individual entering the order into 

CME Globex. For orders entered by an automated trading system (“ATS”), the Tag 50 ID must be unique 

to the person, or the identified team of persons on the same shift, who are responsible for the operation of 

the ATS. All Tag 50 IDs must be unique at the level of the clearing member firm. See Market Regulation 

Advisory Notice RA0915-5, “Operator ID (‘Tag 50’) Required on All CME Globex Orders,” available 

from CME Group at http://www.cmegroup.com/rulebook/files/CME_Group_RA0915-5.pdf (visited May 

15, 2010). 
 

Appendix D - 7 

The numbers for Buy Accts and Sell Accts provide a rough idea of the breadth of 

participation from an account owner/controller standpoint. The numbers for Buy User 

IDs and Sell User IDs provide a rough idea of the breadth of participation from the 

standpoint of users directly interfacing with the Globex system. Many participants were 

both buyers and sellers and they would be included in both the Buy and Sell columns. 

Source of data: CME Group as of May 13, 2010 
 

Appendix D - 8 

CME E­Mini SP Futures

June 2010 Contract

Summarized Activity By Hour (Eastern Daylight Time)

Trade Date May 6, 2010
 

Appendix D - 9 

CME E­Mini SP Futures  

June 2010 Contract

Summarized Activity By Minute 1:00 PM­3:15 PM (Eastern Daylight Time)  

Trade Date May 6, 2010
 

Appendix D - 10 
 

Appendix D - 11 
 

Appendix D - 12 
 

Appendix D - 13 

CME E­mini SP Futures June 2010 Contract

Summarized Activity By Second 2:41 PM­2:50 PM (Eastern Daylight Time)

Trade Date May 6, 2010
 

Appendix D - 14 
 

Appendix D - 15 
 

Appendix D - 16 
 

Appendix D - 17 
 

Appendix D - 18 
 

Appendix D - 19 
 

Appendix D - 20 
 

Appendix D - 21 
 

Table of Tables 

Table 1: Trades Executed at a Loss .................................................................................. 20 

Table 2: Trades Executed at a Gain .................................................................................. 20 

Table 3: Maximum Trade Loss for Dow 30 Stocks.......................................................... 21 

Table 4: Distribution of Securities and Securities with Broken Trades............................ 30 

Table 5: Number of Trades Executing on Each Market .................................................. 31 

Table 6: Percentage of Trades Executing on Each Market.............................................. 32 

Table 7: Broken Trades by Time Period - May 6, 2010 .................................................. 33 

Table 8: Trades Executed at a Loss ................................................................................. 36 

Table 9: Trades Executed at a Gain ................................................................................. 37 

Table 10: Fund Companies .............................................................................................. 43 

Table 11: ETFs with Broken Trades................................................................................ 44 

Table 12: Top 10 ETFs with Broken Trades by Trading Volume – Full Day, May 6 .... 48 

Table 13: Top 10 ETFs with Broken Trades by Trading Volume – May 6 from 2 p.m. to 

3 p.m. ................................................................................................................................ 48 

Table 14: Top 10 Broken Stocks by Trading Volume – Full Day May 6 ....................... 49 

Table 15: Top 10 Broken Stocks by Trading Volume – May 6 from 2 p.m. to 3 p.m. ... 49 

Table 16: Summary Data for Single-Security Plots.......................................................... 58 

Table 17: CME Equity Index Futures Stop Logic Events by Date: 2007-2010 ............... 62 

Table of Figures 

Figure 1: Select Equity Indices and Equity Index Futures, May 6, 2010 ......................... 11 

Figure 2: Historical Daily VIX Values, January 2005 to May 2010 ................................ 12 

Figure 3: CBOE SPX Volatility Index Intraday Levels.................................................... 13 

Figure 4: Ten-Year U.S. Treasury Note Yield.................................................................. 14 

Figure 5: Credit Default Spreads on Greek Sovereign Debt............................................. 15 

Figure 6: Euro-Dollar and Euro Yen Exchange Rates on May 6, 2010 ........................... 16 

Figure 8: Distribution of May 6 Daily Lows ................................................................... 18 

Figure 9: Average Daily Profile of NYSE LRP Events................................................... 23 

Figure 10: Timing of Daily Lows, May 6, 2:00pm to 3:00pm ......................................... 24 

Figure 11: Timing of Daily Highs, May 6, 2:00 p.m. to 3:00 p.m. ................................. 25 

Figure 12: Liquidity Provided/Taken by Top 10 Liquidity Providers Across All Equity 

Markets 2:00 p.m. - 3:00 p.m. May 6, 2010 ..................................................................... 27 

Figure 13: Percent of Liquidity Provided/Taken by Top 10 Liquidity Providers against 

Total Volume Across all Equity Markets 2:00 p.m. – 3:00 p.m. May 6, 2010................. 28 

Figure 14: Price Chart for Accenture plc (Ticker = ACN) .............................................. 35 

Figure 15: Distribution of May 6 Daily Lows for ETFs.................................................. 38 

Figure 16: Timing of ETF Daily Lows, May 6, 2:00pm to 3:00 pm ................................ 39 

Figure 17: Timing of ETF Daily Highs, May 6, 2:00 p.m. to 3:00 p.m. .......................... 40 

Figure 18: Broken-Trade ETFs and ETF Universe.......................................................... 41 

Figure 19: Price Chart for iShares MSCI EAFE Growth Index Fund (Ticker = EFG) .... 45 

Figure 20: Price Chart for iShares Russell 1000 Growth Index Fund (Ticker = IWF) .... 46 
 

Figure 21: Price Chart for Vanguard Total Stock Market Fund (Ticker = VTI) .............. 47 

Figure 22: Price Chart for The Proctor & Gamble Company (Ticker = PG) ................... 51 

Figure 23: Price Chart for 3M Co. (Ticker = MMM)....................................................... 52 

Figure 24: Price Chart for Eaton Vance Tax-Managed Buy-Write Opportunities Fund 

(Ticker = ETV) ................................................................................................................. 53 

Figure 25: Price Chart # 1 for Sotheby’s (Ticker = BID)................................................ 54 

Figure 26: Price Chart #2 for Sotheby’s (Ticker = BID).................................................. 55 

Figure 27: Price Chart for International Business Machines Corporation (Ticker = IBM)

........................................................................................................................................... 56 

Figure 28: Price Chart for Intel Corporation (Ticker = INTC)......................................... 57 

Figure 29: CME E-mini S&P 500 Futures Trade Price and Volume ............................... 60 

Figure 30: Price and Trading Volume in the June 2010 E-mini S&P 500 Futures Contract

........................................................................................................................................... 64 

Figure 32: Bid/Offer Quantities: 5th Best in the............................................................... 66 

Figure 33: Cumulative Number of Transaction Sides of Liquidity Providers and 

Liquidity Takers in the June 2010 E-mini S&P 500 Futures Contract............................. 68