```

[Federal Register Volume 89, Number 235 (Friday, December 6, 2024)]
[Notices]
[Pages 97131-97138]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-28538]

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SECURITIES AND EXCHANGE COMMISSION

[Release No. 34-101780; File No. SR-OCC-2024-016]

Self-Regulatory Organizations; The Options Clearing Corporation; 
Notice of Filing of Proposed Rule Change by The Options Clearing 
Corporation Concerning Enhancements to the System for Theoretical 
Analysis and Numerical Simulations (``STANS'') and OCC's Comprehensive 
Stress Testing (``CST'') Methodology, To Better Capture the Risks 
Associated With Short-Dated Options

December 2, 2024.
    Pursuant to Section 19(b)(1) of the Securities Exchange Act of 1934 
(``Exchange Act'' or ``Act''),\1\ and Rule 19b-4 thereunder,\2\ notice 
is hereby given that on November 22, 2024, The Options Clearing 
Corporation (``OCC'') filed with the Securities and Exchange Commission 
(``SEC'') the proposed rule change as described in Items I, II, and III 
below, which Items have been prepared primarily by OCC. The Commission 
is publishing this notice to solicit comments on the proposed rule 
change from interested persons.
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    \1\ 15 U.S.C. 78s(b)(1).
    \2\ 17 CFR 240.19b-4.
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I. Clearing Agency's Statement of the Terms of Substance of the 
Proposed Rule Change

    This proposed rule change Pursuant to the provisions of Section 
19(b)(1) of the Securities Exchange Act of 1934 (``Exchange Act'' or 
``Act''),\3\ and Rule 19b-4 thereunder,\4\ The Options Clearing 
Corporation (``OCC'') is filing with the Securities and Exchange 
Commission (``Commission'') a proposed rule change in connection with 
enhancements to the modeling approach for implied volatility components 
within OCC's margin methodology, the System for Theoretical Analysis 
and Numerical Simulations (``STANS'') and OCC's Comprehensive Stress 
Testing (``CST'') methodology, to better capture the risks associated 
with short-dated options. Specifically, this proposed rule change 
would, as described below: (1) align the day-count convention between 
option price smoothing and implied volatility scenario generation, and 
(2) extend the term structure of the implied volatility shocks to cover 
implied volatility risk associated with options of less than one-month 
expiration.
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    \3\ 15 U.S.C. 78s(b)(1).
    \4\ 17 CFR 240.19b-4.
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    The proposed changes to OCC's STANS Methodology Description \5\ and 
Comprehensive Stress Testing & Clearing Fund Methodology, and Liquidity 
Risk Management Description \6\ (``CST Methodology Description'') are 
contained in Exhibits 5A and 5B, to File No. SR-OCC-2024-016, 
respectively. Material proposed to be added is marked by underlining 
and material proposed to be deleted is marked with strikethrough text. 
Within the documents, new, revised, and deleted text related to the 
proposed rule change have been incorporated in section 2.1.3 (Implied 
Volatilities Scenarios) and 2.1.4 (S&P 500 Implied Volatilities 
Scenarios) of the STANS Methodology Description and section 3.3.2 
(Volatility Shock Model) of the

[[Page 97132]]

CST Methodology Description. The proposed rule change does not require 
any changes to the text of OCC's By-Laws or Rules. All terms with 
initial capitalization that are not otherwise defined herein have the 
same meaning as set forth in the OCC By-Laws and Rules.\7\
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    \5\ OCC has filed the STANS Methodology Description and 
amendments thereto with the Commission. See Exchange Act Release 
Nos. 100528 (July 15, 2024), 89 FR 58836 (July 19, 2024) (SR-OCC-
2024-008); 98101 (Aug. 10, 2023), 88 FR 55775 (Aug. 16, 2023) (SR-
OCC-2022-012); 95319 (July 19, 2022), 87 FR 44167 (July 25, 2022) 
(SR-OCC-2022-001); 93371 (Oct. 18, 2021), 86 FR 58704 (Oct. 22, 
2021) (SR-OCC-2021-011); 91833 (May 10, 2021), 86 FR 26586 (May 14, 
2021) (SR-OCC-2021-005); 91079 (Feb. 8, 2021), 86 FR 9410 (Feb. 12, 
2021) (SR-OCC-2020-016). OCC makes its STANS Methodology Description 
available to Clearing Members. An overview of the STANS methodology 
is on OCC's public website: https://www.theocc.com/Risk-Management/Margin-Methodology.
    \6\ OCC has filed the CST Methodology Description and amendments 
thereto with the Commission. See Exchange Act Release Nos. 100455 
(July 2, 2024), 89 FR 56452 (July 9, 2024) (SR-OCC-2024-006); 90827 
(Dec. 30, 2020), 86 FR 659 (Jan. 6, 2021) (SR-OCC-2020-015); 89014 
(June 4, 2020), 85 FR 35446 (June 10, 2020) (SR-OCC-2020-003); 87718 
(Dec. 11, 2019), 84 FR 68992 (Dec. 17, 2019) (SR-OCC-2019-010); 
87717 (Dec. 11, 2019), 84 FR 68985 (Dec. 17, 2019) (SR-OCC-2019-
009); 83735 (July 27, 2018), 83 FR 37855 (Aug. 2, 2018) (SR-OCC-
2018-008).
    \7\ OCC's By-Laws and Rules can be found on OCC's public 
website: https://www.theocc.com/Company-Information/Documents-and-Archives/By-Laws-and-Rules.
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II. Clearing Agency's Statement of the Purpose of, and Statutory Basis 
for, the Proposed Rule Change

    In its filing with the Commission, OCC included statements 
concerning the purpose of and basis for the proposed rule change and 
discussed any comments it received on the proposed rule change. The 
text of these statements may be examined at the places specified in 
Item IV below. OCC has prepared summaries, set forth in sections (A), 
(B), and (C) below, of the most significant aspects of these 
statements.

(A) Clearing Agency's Statement of the Purpose of, and Statutory Basis 
for, the Proposed Rule Change

    OCC is the sole clearing agency for standardized equity options 
listed on national securities exchanges registered with the Commission. 
In its role as a clearing agency, OCC acts as a central counterparty 
(``CCP''), guarantying all contracts it clears. That is, OCC becomes 
the buyer to every seller and the seller to every buyer, which exposes 
OCC to risk because OCC is obligated to perform even when one of its 
members defaults. These risks include: (i) credit risk, which is the 
risk that OCC would not maintain sufficient financial resources to 
cover exposures; and (ii) liquidity risk, which is the risk that OCC 
would not have sufficient liquid resources to meet payment obligations 
when due.
    OCC manages its credit and liquidity risks through various 
safeguards to ensure that it has sufficient financial resources in both 
form and amount in the event of a Clearing Member failure. To begin 
with, OCC periodically collects margin collateral from its Clearing 
Members, which is designed to cover the credit exposures they 
individually present to OCC with a high degree of confidence. OCC also 
maintains a Clearing Fund, which is a mutualized pool of financial 
resources to which each Clearing Member is required to contribute to 
ensure that OCC maintains sufficient qualifying liquid resources to 
manage its liquidity risk, and to address the tail risk that the margin 
collateral OCC collects from each Clearing Member might be insufficient 
to cover OCC's credit exposure to a defaulting member in extreme but 
plausible market conditions. In general, OCC performs daily stress 
testing of its financial resources using scenarios designed to assess 
whether the resources collected are adequate and inform the size of 
OCC's financial resources (``Sizing Scenarios'') and measure the 
potential exposures Clearing Members may present to OCC to determine 
whether calls for additional collateral in either margin or in the 
Clearing Fund would be needed (``Sufficiency Scenarios''). Clearing 
Member margin amounts are collected based on calculations obtained from 
STANS, while Clearing Fund contributions are default scenario-based 
amounts generated by the CST methodology.
    Clearing Member portfolios contain a mix of products and positions 
in options of various tenors, as well as other cleared positions (e.g., 
futures, stock loans) and collateral (e.g., valued securities, delivery 
obligations, US treasuries, Canadian Government bonds, and cash). Over 
the past several years, the options markets in particular have 
experienced a significant increase in the trading of short-dated 
options (``SDOs''), which refer to option contracts with a maturity of 
less than or equal to one month to expiration.\8\ However, the increase 
in the volume of SDO trading and the larger concentration of SDO 
positions held from hedging and speculation activities present unique 
challenges to the risk management framework.
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    \8\ See, e.g., Cboe, The Rise of SPX & 0DTE Options (July 27, 
2023), available at https://go.cboe.com/l/77532/2023-07-27/ffc83k.
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    For these reasons, OCC carried out a study to examine the specific 
risks posed by SDOs (the ``Study'') \9\ including risks posed by the 
increase to volatility due to the feedback between options and equity 
hedging activity. OCC also analyzed the valuation of SDOs and option 
scenario pricing in OCC's 2-day margin period of risk (``MPOR'') \10\ 
and assessed the margin risk of portfolios dominated by SDOs through 
sensitivity analysis of realized P&L and risk coverage metrics. OCC 
concluded from the Study that valuation of SDOs and options scenario 
pricing in the 2-day MPOR was in general reasonable, but that 
opportunities exist to improve model performance for Clearing Member 
portfolios dominated by SDOs. Moreover, a reasonableness analysis of 
the mark-to market pricing and theoretical price simulation of SDOs in 
the MPOR indicated that certain existing margin model assumptions 
having a direct impact on SDO risk coverage needed further enhancement 
and update.
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    \9\ OCC has included the Study as confidential Exhibit 3A to 
File No. SR-OCC-2024-016.
    \10\ OCC collects its credit resources with an assumption of a 
two-day MPOR (i.e., two days after the last good margin collection) 
and potential liquidity obligations are evaluated using the same 
concept and assuming the liquidation processes details in OCC's 
Default Management Policy.
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    Specifically, the Study referred to a difference between option 
price smoothing \11\ that uses calendar day convention, and implied 
volatility \12\ simulation that uses trading day convention. The usage 
of two day count conventions \13\ results in differences in implied 
volatility, especially when non-trading days make up a large portion of 
the time-to-expiration (e.g., on Fridays for options that expire the 
following Monday). In this regard, SDOs are far more sensitive to 
differences in day-count convention than contracts with longer 
expiries. In addition, OCC's model for simulating the theoretical 
prices assumes that the implied volatility shocks of the one-month 
tenor (``1M'') are sufficient to cover the implied volatility changes 
for SDO tenors.\14\ However, empirical results indicate that the 
implied volatility changes from SDOs can be much larger than those for 
options with one month to expiration.\15\
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    \11\ The smoothing algorithm is the process that OCC uses to 
estimate fair values for plain vanilla listed options based on 
closing bid and ask price quotes. See Exchange Act Release No. 86731 
(Aug. 22, 2019), 84 FR 45188, 45189 (Aug. 28, 2019) (File No. SR-
OCC-2019-005).
    \12\ Generally speaking, the implied volatility of an option is 
a measure of the expected future volatility of the option's 
underlying security at expiration, which is reflected in the current 
option premium in the market.
    \13\ The term ``day count convention'' refers to a standardized 
methodology for calculating the number of days between two dates. 
Both calendar and business day conventions are used by OCC in STANS 
and CST calculations.
    \14\ The ``tenor'' of an option is the amount of time remaining 
to its expiration or maturity.
    \15\ OCC has observed that the day-over-day at the money implied 
volatility changes for the 1W tenor are approximately twice that of 
the 1M tenor on certain risk factors such as SPX, RUT, QQQ, AAPL, 
TSLA.
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    OCC proposes to improve the theoretical price simulation of SDOs 
and enhance the modeling of the implied volatility risk associated with 
SDOs by: (1) aligning the day-count convention used between option 
price smoothing and its models for simulating implied volatility, and 
(2) extending the term structure \16\ to cover implied volatility risk 
associated with options expiring in less than one-month. The

[[Page 97133]]

proposed changes will be introduced to the Implied Volatilities 
Scenarios Model and S&P 500 Implied Volatility Simulation Model in 
STANS and the Volatility Shock component in CST. The impact of the 
proposed enhancements on Clearing Member margin and on CST is presented 
further below.
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    \16\ The ``term structure'' of implied volatility is the curve 
that depicts the relationship between the implied volatilities of 
options with different expiration (or maturity) dates on the same 
underlying. Expiration and maturity are used interchangeably but 
reflect the same meaning.
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1. Purpose
Background
    OCC's risk framework includes its STANS methodology used to 
calculate Clearing Member margin amounts, and its CST methodology used 
to stress test Clearing Member portfolios in order to determine the 
appropriate size of the Clearing Fund and allocate portions to Clearing 
Members commensurate with the risk they present to OCC.
STANS Overview
    STANS is OCC's proprietary risk management system for calculating 
Clearing Member margin requirements. The STANS methodology utilizes 
large-scale Monte Carlo simulations to forecast price and volatility 
movements in determining a Clearing Member's margin requirement.\17\ 
OCC uses a smoothing algorithm to generate theoretical prices and 
volatilities for option contracts based on the fair value for plain 
vanilla listed options from closing bid and ask price quotes.\18\ OCC 
does this by first filtering out certain poor-quality quotes on 
contracts based on certain conditions and estimates the forward prices 
of the securities underlying these options. OCC then generates the 
theoretical option prices based on the filtered bid and ask quotes and 
constructs a volatility surface \19\ using the smoothed prices to 
approximate option contract prices. The output of the Smoothing 
Algorithm, consisting of various theoretical option contract prices and 
volatilities, is then used downstream as a starting point to simulate 
variations in implied volatility for option contracts.
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    \17\ See OCC Rule 601.
    \18\ See Exchange Act Release No. 86731 (Aug. 22, 2019), 84 FR 
45188 (Aug. 28, 2019) (SR-OCC-2019-005).
    \19\ The ``volatility surface'' refers to a three-dimensional 
plot of the implied volatilities of the various options on the same 
stock reflecting time to maturity, and different strike prices for 
the option.
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    Using the Black-Scholes options pricing model, the implied 
volatility is the standard deviation of the underlying asset price 
necessary to arrive at the market price of an option of a given strike, 
time to maturity, underlying asset price and the current discount 
interest rate. In effect, the implied volatility is responsible for 
that portion of the premium that cannot be explained by the current 
intrinsic value of the option (i.e., the difference between the price 
of the underlying and the exercise price of the option), discounted to 
reflect its time value. OCC considers variations in implied volatility 
within STANS to ensure that the anticipated cost of liquidating options 
positions in an account recognizes the possibility that the implied 
volatility could change during the two-business day liquidation time 
horizon and lead to corresponding changes in the market prices of the 
options. Specifically, OCC models variations in implied volatility 
using its (1) Implied Volatilities Scenarios Model for non-S&P 500 
based products, and (2) S&P 500 Implied Volatility Simulation Model for 
products in the S&P 500 group.\20\
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    \20\ See generally Exchange Act Release No. 95319, supra note 3, 
at 44168-69.
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Implied Volatilities Scenarios Model
    Using its current Implied Volatilities Scenarios Model, OCC models 
the variations in implied volatility used to re-price non-S&P 500 based 
options within STANS. Variations in implied volatility are modeled 
through a volatility surface by incorporating certain risk factors 
(i.e., implied volatility pivot points) based on a range of tenors and 
option deltas \21\ into the models in STANS. These implied volatility 
pivot points consist of three tenors of one month, three months and one 
year, and three deltas of 0.25, 0.5, and 0.75, resulting in nine 
implied volatility risk factors.\22\ These pivot points are chosen such 
that their combination allows the model to capture changes in level, 
skew (i.e., strike price), convexity, and term structure of the implied 
volatility surface.\23\
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    \21\ The ``delta'' of an option represents the sensitivity of 
the option price with respect to the price of the underlying 
security.
    \22\ See Exchange Act Release No. 94165 (Feb. 7, 2022), 87 FR 
8072, 8073 (Feb. 11, 2022) (SR-OCC-2022-001).
    \23\ Id.
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    The Implied Volatility Scenarios Model has certain limitations 
related to SDOs. First, the underlying prices and implied volatilities 
generated from the Smoothing Algorithm, which are an input to the 
Implied Volatility Scenarios Model, are generated using a calendar day 
convention, which is not consistent with the trading day convention 
used in the calibration of the model parameters. The misalignment in 
day-count conventions may result in over- or under-estimation of option 
prices based on the implied volatility scenarios. SDOs are more 
sensitive to day-count convention alignment than contracts with longer 
expirations due to the proportionally larger difference in time to 
expiry between the trading day convention and calendar day convention 
for shorter dated tenors.
    Second, the model imposes a flat term structure on SDOs, which 
forces the use of the implied volatility shock from the 1M tenor on all 
option contracts expiring in less than one month. Because the term 
structure for the Implied Volatilities Scenarios Model starts at the 1M 
tenor, the current model is not consistent with the observed dynamics 
of the underlying assets and the implied volatility surface for SDOs. 
This may lead to inadequate coverage for portfolios with concentrations 
in SDOs.
S&P 500 Implied Volatility Simulation Model
    OCC uses the S&P 500 Implied Volatility Simulation Model for the 
S&P 500 product group.\24\ The purpose of the S&P 500 Implied 
Volatility Simulation Model is to establish a consistent and robust 
framework for implied volatility simulation and provide natural offsets 
for volatility products with similar characteristics to S&P 500 implied 
volatility. The output of the S&P 500 Implied Volatility Simulation 
Model is used by OCC's options pricing model, as well as the Volatility 
Index Futures Model. The S&P 500 Implied Volatility Simulation Model is 
a Monte Carlo simulation model that captures the risk dynamics in the 
S&P 500 implied volatility surface utilizing standardized log-moneyness 
\25\ and a fixed number of key tenors as well as skew to generate an 
S&P 500 1M at-the-money (``ATM'') risk factor.\26\ OCC then uses the 
generated implied volatility scenarios to produce option prices in 
margin estimation and stress testing.\27\
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    \24\ See generally Exchange Act Release No. 95319, supra note 3, 
at 44168-69.
    \25\ The term ``moneyness'' of an option refers to the 
relationship between the strike price and the price of the option 
underlying.
    \26\ See Exchange Act Release No. 94165, supra note 20, at 8075.
    \27\ Id.
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    The S&P 500 Implied Volatility Simulation Model has certain 
limitations related to SDOs. Like the Implied Volatilities Scenarios 
Model discussed above, the S&P 500 Implied Volatility Simulation Model 
uses a trading day convention in the calibration of the model, which is 
not consistent with the calendar day convention used in the generation 
of the input from the Smoothing Algorithm. As for the Implied 
Volatilities Scenarios Model, this misalignment may result in

[[Page 97134]]

over- or under-estimation of option prices, particularly for SDOs. 
Second, the S&P 500 Implied Volatility Simulation Model uses a fixed 
number of key tenors beginning with the 1M tenor. Because the term 
structure for the S&P 500 Implied Volatility Simulation Model starts at 
the 1M tenor, the current model is not consistent with the observed 
dynamics of the underlying assets and the implied volatility surface 
for SDOs, which may lead to inadequate coverage for portfolios with 
concentrations in SDOs.
CST Overview
    As described in the CST Methodology Description, OCC uses CST to 
analyze the adequacy of its financial resources in extreme but 
plausible scenarios. It enables OCC to better manage its risks by 
promoting OCC's ability to thoroughly monitor its potential exposure 
under varied sets of stressed market scenarios and provides it with the 
ability to review the sufficiency of its financial resources. Moreover, 
the methodology includes stress tests designed to size and monitor the 
sufficiency of both prefunded credit and liquidity resources. OCC 
relies upon a set of stress scenarios constructed pursuant to the CST 
Methodology Description, including both Sizing and Sufficiency 
scenarios.
    CST is a scenario-based, one-factor risk model with four principal 
elements.\28\ First, a set of risk drivers is selected based on the 
portfolio exposures of all Clearing Members in the aggregate.\29\ 
Second, each individual underlying security from the portfolio of a 
Clearing Member is mapped to a key risk driver, to estimate the 
sensitivity for the beta \30\ of the security with respect to the 
corresponding risk driver.\31\ Third, stress scenarios are generated by 
assigning a stress shock to each of the risk drivers, which drives the 
shock of an individual underlying security.\32\ Fourth, the aggregate 
risk exposure or shortfall of each portfolio is generated for each 
stress scenario for each Clearing Member and the Clearing Member Group 
level.\33\ The CST methodology consists of several component models, 
including the Volatility Shocks, the VIX Futures Prices Shocks, and 
Idiosyncratic Scenarios models.
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    \28\ See Exchange Act Release No. 83406 (Jun 11, 2018), 83 FR 
28018, 28022 (June 15, 2018) (SR-OCC-2018-008).
    \29\ Id.
    \30\ The ``beta'' of a security is the sensitivity of the price 
of the security relative to the price of the security.
    \31\ Exchange Act Release No. 83406, supra note 26, at 28022.
    \32\ Id.
    \33\ Id.
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Volatility Shocks
    The Volatility Shocks model component of the CST methodology 
provides a method to generate implied volatility in a stress scenario 
for all individual option products that are cleared by OCC.\34\ This 
model component is used to shock any option product cleared by OCC. 
Shocked implied volatility is needed at the product, expiration, and 
strike level to evaluate individual option implied volatilities in 
stressed market conditions, which is then used to determine options 
prices and calculate the profit and loss of Clearing Member accounts in 
stress scenarios. For all systemic stress scenarios,\35\ the Cboe 
Volatility Index (``VIX'') is used as the main risk driver in 
determining shocked implied volatility.\36\
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    \34\ See generally id. at 28023.
    \35\ The term ``systemic stress scenarios'' are scenarios 
designed to the capture risk to OCC in an extreme event impacting 
all positions driven by risk drivers.
    \36\ Exchange Act Release No. 83406, supra note 26, at 28023.
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    Two methods are used to generate strike-level shocked implied 
volatility from VIX shocks: (1) an approach for equity products, 
including equity ETFs, indexes and futures that have the S&P 500 Index 
(``SPX'') as the risk driver; and (2) an approach used for options on 
all risk factors that do not have SPX as a risk driver. The term 
structure of SPX-driven implied volatilities is based on volatility 
betas versus VIX, while a standardized log-moneyness metric is used to 
model the implied volatility curves.\37\ For non-SPX driven risk 
factors, the implied volatility shocks are based on historical 
volatility beta regressed directly against the VIX.\38\
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    \37\ Id.
    \38\ Id.
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    The Volatility Shocks component of CST has certain limitations 
related to SDOs. First, like the STANS models discussed above, the 
Volatility Shocks component uses a trading day convention in the 
calibration of model parameters, which is not consistent with the 
calendar day convention used by the Smoothing Algorithm. As discussed 
above, this misalignment may result in over- or under-estimation of 
option prices, particularly for SDOs. Second, Volatility Shock imposes 
a flat term structure for SDOs when calculating shocked implied 
volatility, which is not consistent with the observed dynamics of the 
underlying assets and the implied volatility surface for SDOs. These 
limitations may result in inadequate shocks for SDOs.
VIX Futures Price Shocks
    The VIX is an index for measuring implied volatility based on 
options on the SPX with approximately 30 days to expiration. OCC 
derives VIX futures prices shocks from SPX volatility betas and VIX 
index shocks using the VIX Futures Price Shocks component of CST.\39\ 
The term structure of the VIX futures prices shocks is modeled from 
that of the SPX ATM implied volatility shocks. OCC first determines the 
term structure of the SPX volatility beta, by running regression of the 
2-day returns of SPX ATM implied volatility with respect to the 2-day 
returns of the VIX index for different expirations, ranging from 1M to 
twelve months (``12M'').\40\ Through linear interpolation on the term 
structure curve of SPX volatility beta OCC determines the volatility 
beta at the VIX futures expiration and 30 days after, which are the 
basis to calculate VIX futures price shocks. As a final step a 
constraint is then applied to ensure that the VIX futures price shocks 
do not exceed the VIX index shock.
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    \39\ See Exchange Act Release No. 87386 (Oct. 23, 2019), 84 FR 
57911, 57913-14 (Oct. 29, 2019) (SR-OCC-2019-009).
    \40\ See id. at 57916 n. 29 and accompanying text.
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    Like the Volatility Shocks model, the VIX Futures Price Shocks 
component imposes a flat term structure for SDOs when calculating 
shocked implied volatility, which is not consistent with the observed 
dynamics of the underlying assets and the implied volatility surface 
for SDOs. This limitation of the VIX Futures Price Shocks model may 
result in inadequate shocks for SDOs.\41\
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    \41\ Unlike the other model discussed herein, the VIX Futures 
Price Shocks model uses the SPX volatility beta with extended tenors 
less than 1 month from the Volatility Shocks model component and 
Dynamic VIX Calibration model component as inputs, and day-count 
convention alignment is not within the scope for this model 
component.
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Idiosyncratic Scenarios
    OCC uses Idiosyncratic Scenarios to generate and capture the risk 
from extreme non-systemic events that may impact OCC's financial 
resources.\42\ Specifically, OCC captures the risk of extreme non-
systemic market moves on single name equity securities (non-ETF, non-
Index) through individual up and down shocks (assuming all other 
products are unchanged). Single-name equities are classified into large 
and small capitalization (cap) for the price shocks. Four types of 
idiosyncratic moves are constructed based on the

[[Page 97135]]

market capitalization and direction of the price shock: large cap up, 
large cap down, small cap up and small cap down.\43\ A fixed price 
shock for each of the four scenarios is calibrated from historical 
price return data such that probability of idiosyncratic moves is 
comparable to systemic scenarios and probability in all four scenarios 
is approximately equal. Based on price shocks, ATM implied volatility 
shocks are calibrated for each of the four scenarios.\44\
---------------------------------------------------------------------------

    \42\ See generally Exchange Act Release No. 87386, supra note 
37, at 57913.
    \43\ Id.
    \44\ Id.
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    The Idiosyncratic Scenarios component of CST shares the limitations 
related to SDOs discussed above with respect to the other models. 
Specifically, the Idiosyncratic Scenarios component uses a trading day 
convention in the calibration of model parameters, which is not 
consistent with the Smoothing Algorithm's calendar day convention. As 
discussed above, this misalignment may result in over- or under-
estimation of option prices, particularly for SDOs. Second, like the 
Volatility Shocks model, Idiosyncratic Scenarios imposes a flat term 
structure for SDOs when calculating shocked implied volatility, which 
is not consistent with the observed dynamics of the underlying assets 
and the implied volatility surface for SDOs. These limitations may 
result in inadequate shocks for SDOs.
Proposed Change
    OCC proposes to capture the risks associated with SDOs by applying 
enhancements to the implied volatility modeling approach to: (1) align 
the day-count convention between option price smoothing and implied 
volatility scenario generation, and (2) extend the term structure to 
cover implied volatility risk associated with options with less than 
one month to expiration. These enhancements will be implemented for 
model components in STANS and CST.
Day-Count Convention Alignment
    At present, the implied volatility output from smoothing, 
determined using a calendar day convention, is directly applied in the 
initial implied volatility scenarios in STANS and CST. However, the 
calibration of the parameters used in implied volatility scenarios uses 
a trading day convention, which is also used to model forecasted 
variance as well as the shocks in CST. OCC proposes to align the day-
count convention to be consistent between calibration and price 
smoothing in both STANS and CST.
    In STANS, OCC proposes to align the day-count convention between 
price smoothing and its model components used for forecasting changes 
in implied volatility through amendments to the sections of the STANS 
Methodology Description that address the Implied Volatilities Scenarios 
Model and the S&P 500 Implied Volatility Simulation Model.\45\ For the 
Implied Volatilities Scenarios Model (pivot-based), implied volatility 
levels would be initially converted into trading day convention before 
application of pivot scenario shocks. The shocked implied volatility 
scenarios would then be converted back to calendar day convention 
before being used to calculate shocked option price scenarios. For the 
S&P 500 Implied Volatility Simulation Model, the process for generating 
the shocked implied volatility scenarios for listed tenors would 
convert the initial implied volatility from using calendar day 
convention to using trading day convention followed by generation of 
the ATM implied volatility log-return scenarios for listed tenors. The 
skew shock scenarios would be generated next, followed by the shocked 
implied volatility scenarios. The outputs of the shocked implied 
volatility scenarios would then be converted back to calendar day 
convention before calculating the theoretical option price scenarios. 
These conversion steps taken together would then align the day-count 
convention used in both option price smoothing and implied volatility 
simulations.
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    \45\ OCC would also make conforming changes to the whitepapers 
for these models. OCC has provided updates to its STANS whitepapers 
for the impacted models in confidential Exhibit 3B and 3C to File 
No. SR-OCC-2024-016.
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    Similarly, OCC would align the day-count convention of the Implied 
Volatility Shocks in CST through conversion of the initial volatility 
surface from the output of the Smoothing Algorithm to business day 
convention before application of any volatility shocks.\46\ After the 
volatility shock is applied, the shocked implied volatility would then 
be scaled back to calendar day convention, before being used downstream 
for option pricing in CST. These changes would be reflected in 
amendments to the CST Methodology Description's section that addresses 
the Volatility Shock Model. With respect to the Idiosyncratic 
Scenarios, the CST methodology already provides that after calculating 
the shocked ATM volatility, the shocked implied volatility for all the 
strikes in the expiration follows the same methodology as for the 
Volatility Shock Model.
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    \46\ OCC would also make conforming changes to the whitepapers 
for these models. OCC has provided updates to its CST whitepapers 
for the impacted models in confidential Exhibit 3D and 3F to File 
No. SR-OCC-2024-016.
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Extension of the Term Structure
    At present, the STANS Implied Volatilities Scenarios model uses a 
flat term structure for options with listed tenors that are shorter 
than one month, which means that the implied volatility shock is 
derived from the 1M key tenor or pivot. OCC proposes to change the 
Implied Volatility Scenarios term structure for the implied volatility 
simulation of all non-SPX related risk factors, such that for points 
with shorter than one month to maturity, a squared-root decay is 
applied with respect to one month to expiration up to a predetermined 
shortest time to maturity. For the S&P 500 Implied Volatility 
Simulation Model term structure and SPX related risk factors, the 
applicable sections of the STANS Methodology Description would be 
updated to provide for a shorter key tenor than the current 1M time to 
maturity.
    With respect to the CST Volatility Shocks model, which uses the 
volatility beta from the 1M tenor for SDOs, OCC proposes to extend the 
volatility beta approach to cover constant maturity tenors of less than 
one-month expiration by adding constant maturity tenors at the 1-week 
(``1W'') and 2-week (``2W'') key points of the term structure. 
Similarly, for the VIX Futures Price Shocks model, OCC proposes that 
the volatility beta for listed tenors that are less than the 1W tenor 
and down to the 3-day (``3D'') tenor would be linearly interpolated 
from the 1W tenor and 2W tenor volatility betas, i.e., the 1W and 2W 
tenor expirations would be added as inputs to the term structure of SPX 
volatility betas. As for Idiosyncratic Scenarios, the term structure 
would be extended from 1M down to the 1W tenor and 2W tenor. These 
changes would be applied to the section of the CST Methodology 
Description that addresses the Volatility Shock Model, the same 
methodology for which also applies to the Idiosyncratic Scenarios 
Models as described above. In addition, this change would also apply to 
the VIX Futures Price Shock Model because the Volatility Shock Model's 
method is incorporated by reference in the section that describes the 
volatility beta shocks applied to volatility instruments.
    OCC also proposes to update the day count to the more precise value 
of 365.25 within the CST Methodology Description when referring to 
calendar days in a year and also when used in a formula. This amendment 
to the CST Methodology Description conforms with

[[Page 97136]]

how the system was designed to be consistent with the day-count 
convention specified in the STANS Methodology Description. Since the 
CST system already uses a 365.25 day count convention, the proposed 
change to correct the documentation would have no impact on stress test 
results. Additionally, OCC plans to make several other minor non-
substantial typographical changes throughout the document.
    In addition, OCC proposes to further revise the relevant sections 
of the STANS Methodology Description concerning the S&P 500 Implied 
Volatility Simulation model to eliminate redundant and duplicative 
information. Specifically, OCC proposes to remove sections related to 
the generation of the simulation of certain shocks that are duplicative 
of information covered in the STANS Methodology Description's 
discussion of the theory and specifications for that model. The 
sections related to the simulation of the shocked implied volatility 
scenarios would be amended to instead refer to those previous sections, 
which would be updated to reflect the two changes proposed herein.
Impact Analysis
    OCC has reviewed the potential impact of the proposed changes on 
margin across all Clearing Member tier accounts over a 15-month period, 
between July 2023 and September 2024. OCC observed that the proposed 
enhancements would lead to an average daily total margin \47\ increase 
of 0.58% (approximately $0.2 billion, calculated based on the average 
daily margin of nearly $38 billion) across all accounts and activity 
dates, with the daily total margins falling in a narrow range between 
the largest decrease of 0.81% (approximately $0.3 billion) to the 
largest increase of 3.21% (approximately $1.1 billion). The results 
further demonstrated that the SDO enhancements had a larger measurable 
impact for accounts with high concentrations of short-dated options.
---------------------------------------------------------------------------

    \47\ Margin is calculated as the sum of requirement shortfall 
and stress test add-on charge.
---------------------------------------------------------------------------

    OCC also reviewed the potential impact on CST for the proposed 
model enhancements based on backtesting results over the same time 
period. OCC observed that the proposed changes had a relatively small 
impact on the Cover 1 and Cover 2 shortfalls used in Sufficiency and 
Sizing Scenarios for the leading Clearing Member Groups. The impact 
varied among Clearing Members, influenced by factors such as portfolio 
size, product diversity within those portfolios, and the concentration 
of SDO positions. Smaller Clearing Members with a high concentration of 
SDO positions experienced relatively more meaningful impacts.
    With respect to Sizing Scenarios impacts, OCC observed a decrease 
in the average Cover 2 shortfall for the 1-in-80-Year Rally Scenario of 
0.1% (approximately $12.7 million) with the daily variation falling in 
a narrow range between the largest decrease of 3.18% to the largest 
increase of 0.53%. For the Cover 2 shortfall on the 1-in-80-Year 
Decline Scenario OCC observed an average decrease of 0.47% 
(approximately $65 million) with the daily variation falling in a 
narrow range between the largest decrease of 3.17% to the largest 
increase of 1.16%.
    Simliarly, regarding Sufficiency Scenarios impacts, OCC observed a 
decrease in the average Cover 1 shortfall for the 1987 Crash Scenario 
of 0.39% (approximately $37 million) with the daily variation falling 
in the range between the largest daily decrease of 3.15% and largest 
daily increase of 1.97%. For the Largest Rally from 2008 Sufficiency 
Scenario, the daily average Cover 2 Shortfall increased by around 
0.22%, which is about $16 million. The shortfall ranged between a 
decrease of $208 million and an increase of $116 million, which is 
about a decrease of 3.54% to an increase of 1.90%. For the Largest 
Rally from 2008--Historical Beta Sufficiency Scenario,\48\ the daily 
average Cover 2 Shortfall decreased by around 0.1%, which is about $7 
million. The shortfall ranged between a decrease of $196 million and an 
increase of $143 million, which is about a decrease of 1.93% to an 
increase of 1.41%.
---------------------------------------------------------------------------

    \48\ OCC notes that backtesting data for this scenario is 
limited due to its recent deployment and use in production.
---------------------------------------------------------------------------

    Overall, OCC observed a reduction to the Clearing Fund size of 
around 0.14% (approximately $14 million) based on the changes in Cover 
2 shortfalls in Sizing Scenarios. OCC believes that such changes to 
margin and Cover 1 Sufficiency Scenarios and Cover 2 Sizing Scenarios 
are commensurate with the risks presented by Clearing Members SDO 
trading activities.
Implementation and Timeframe
    The proposed margin model and CST methodology changes will be 
integrated into OCC's current production system, and implemented within 
180 days after the date that OCC receives all necessary regulatory 
approvals for the proposed changes. OCC will announce the 
implementation date of the proposed changes by an Information 
Memorandum posted to its public website at least 2 weeks prior to 
implementation.
2. Statutory Basis
    OCC believes the proposed rule change is consistent with Section 
17A of the Exchange Act \49\ and Rules 17Ad-22(e)(6) \50\ and (e)(7) 
\51\ thereunder. Section 17A(b)(3)(F) of the Act \52\ requires, among 
other things, that the rules of a clearing agency be designed to 
promote the prompt and accurate clearance and settlement of securities 
transactions, and in general, to protect investors and the public 
interest. As described above, OCC could be exposed to increased credit 
and liquidity risk if the margin and Clearing Fund models do not 
adequately capture changes to the dynamic behavior of the implied 
volatility associated with portfolios dominated by SDO positions. As 
discussed above, OCC believes the proposed enhancements improve the 
model performance for portfolios with high SDO concentration. The 
output of these models would be used by OCC to calculate margin and 
Clearing Fund requirements designed to limit its credit and liquidity 
exposures to participants and ensure that OCC is able to continue the 
prompt and accurate clearance and settlement of its cleared products. 
The collection of margin and Clearing Fund helps to protect investors 
and the public interest by ensuring OCC has sufficient resources to 
manage a potential Clearing Member default that may otherwise impose 
unexpected costs on non-defaulting Clearing Members and, ultimately, 
their customers. For these reasons, OCC believes the proposed changes 
are designed to promote the prompt and accurate clearance and 
settlement of securities transactions, and, thereby, to protect 
investors and the public interest in accordance with Section 
17A(b)(3)(F) of the Exchange Act.\53\
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    \49\ 15 U.S.C. 78q-1.
    \50\ 17 CFR 240.17Ad-22(e)(6).
    \51\ 17 CFR 240.17Ad-22(e)(7).
    \52\ 15 U.S.C. 78q-1(b)(3)(F).
    \53\ Id.
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    OCC also believes that the proposed changes are consistent with 
Rule 17Ad-22(e)(6).\54\ In particular, paragraphs (i), (iii), and (v) 
of Rule 17Ad-22(e)(6) \55\ require a covered clearing agency that 
provides central counterparty services to establish, implement, 
maintain and enforce written policies and procedures reasonably 
designed to cover its credit exposures to its participants by 
establishing a risk-based margin system

[[Page 97137]]

that (1) considers, and produces margin levels commensurate with, the 
risks and particular attributes of each relevant product, portfolio, 
and market; (2) calculates margin sufficient to cover its potential 
future exposure to participants in the interval between the last margin 
collection and the close out of positions following a participant 
default; and (3) uses an appropriate method for measuring credit 
exposure that accounts for relevant product risk factors and portfolio 
effects across products. As noted above, OCC's current models in STANS 
may not adequately capture the implied volatility behaviors associated 
with SDO in portfolios that may be dominated by SDO positions, which 
could result in inadequate margin requirements. As described in detail 
above, OCC believes that aligning the day count convention and 
extending the term structure in OCC's margin system to take into 
consideration SDO specific attributes, are appropriate methods to 
enable OCC to measure SDO credit exposure and produce margin 
requirements commensurate with the risks presented by SDO trading 
activities, and as designed enables OCC to calculate margin sufficient 
to cover SDO exposure from Clearing Member accounts with high 
concentrations of short-dated options. The proposed changes are 
designed to enhance model outputs to produce margin requirements that 
are commensurate with the risks presented by portfolios containing SDO 
s positions. As a result, OCC believes that the proposed changes are 
reasonably designed to calculate margin commensurate with risks and 
particular attributes of SDO and sufficient to cover its potential 
future exposure to participants in the interval between the last margin 
collection and the close out of positions following a participant 
default, and uses an appropriate method to measure credit exposures 
that accounts for the relevant SDO product risk factors in a manner 
consistent with Rules 17Ad-22(e)(6)(i), (iii) and (v).\56\
---------------------------------------------------------------------------

    \54\ 17 CFR 240.17Ad-2(e)(6).
    \55\ 17 CFR 240.17Ad-2(e)(6)(i), (iii), (v).
    \56\ Id.
---------------------------------------------------------------------------

(B) Clearing Agency's Statement on Burden on Competition

    Section 17A(b)(3)(I) requires that the rules of a clearing agency 
do not impose any burden on competition not necessary or appropriate in 
furtherance of the purposes of the Act.\57\ The proposed alignment of 
the calendar convention between price smoothing and model calibration, 
and the extension of the term structure for implied volatility and 
volatility shocks, would be used by OCC to manage its credit and 
liquidity risk across all Clearing Members. Accordingly, OCC does not 
believe that the proposed rule change would unfairly hinder access to 
OCC's services.
---------------------------------------------------------------------------

    \57\ 15 U.S.C. 78q-1(b)(3)(I).
---------------------------------------------------------------------------

    While the proposed rule change may impact different accounts to a 
greater or lesser degree depending on the composition of SDO positions 
in each account, OCC does not believe that the proposed rule change 
would impose any burden on competition not necessary or appropriate in 
furtherance of the purposes of the Exchange Act. As discussed above, 
OCC is obligated under the Exchange Act and the regulations thereunder 
to establish, implement, maintain and enforce written policies and 
procedures reasonably designed to cover its credit exposures to its 
participants by establishing a risk-based margin system that, among 
other things, considers, and produces margin levels commensurate with 
the risks and particular attributes of each relevant product, 
portfolio, and market.\58\ Overall, the impact analysis indicates there 
are significant improvements in performance and margin coverage for 
SDOs from the proposed model enhancements.
---------------------------------------------------------------------------

    \58\ See 17 CFR 240.17Ad-2(e)(6)(i).
---------------------------------------------------------------------------

    Moreover, while the composition of SDOs within Clearing Member 
portfolios may drive margin and scenario charges that may be higher or 
lower than under the current regime, nevertheless OCC believes that 
margin coverage improvements occur with the adoption of the proposed 
enhancements. These enhanced model components would utilize a more 
consistent approach to calendar conventions, while the term structure 
is also extended to account for SDO tenors, which directly address 
certain limitations within the current implementation of STANS and CST 
models. In addition, the proposed model enhancements are expected to 
produce margin requirements that are more commensurate to the risks 
generated from holding SDO positions within Clearing Member portfolios, 
and therefore consistent with OCC's obligations under the Exchange Act 
and regulations thereunder. Accordingly, OCC believes that the proposed 
rule change would not impose any burden or impact on competition not 
necessary or appropriate in furtherance of the purposes of the Exchange 
Act.

(C) Clearing Agency's Statement on Comments on the Proposed Rule Change 
Received From Members, Participants or Others

    Written comments were not, and are not, intended to be solicited 
with respect to the proposed change and none have been received.

III. Date of Effectiveness of the Proposed Rule Change and Timing for 
Commission Action

    Within 45 days of the date of publication of this notice in the 
Federal Register or within such longer period up to 90 days (i) as the 
Commission may designate if it finds such longer period to be 
appropriate and publishes its reasons for so finding or (ii) as to 
which the selfregulatory organization consents, the Commission will:
    (A) by order approve or disapprove such proposed rule change, or
    (B) institute proceedings to determine whether the proposed rule 
change should be disapproved.
    The proposal shall not take effect until all regulatory actions 
required with respect to the proposal are completed.

IV. Solicitation of Comments

    Interested persons are invited to submit written data, views and 
arguments concerning the foregoing, including whether the proposed rule 
change is consistent with the Act. Comments may be submitted by any of 
the following methods:

Electronic Comments

     Use the Commission's internet comment form (https://www.sec.gov/rules-regulations/self-regulatory-organization-rulemaking); 
or
     Send an email to [email protected]. Please include 
file number SR-OCC-2024-016 on the subject line.

Paper Comments

     Send paper comments in triplicate to Vanessa Countryman, 
Secretary, Securities and Exchange Commission, 100 F Street NE, 
Washington, DC 20549-1090.

All submissions should refer to file number SR-OCC-2024-016. This file 
number should be included on the subject line if email is used. To help 
the Commission process and review your comments more efficiently, 
please use only one method. The Commission will post all comments on 
the Commission's internet website (https://www.sec.gov/rules/sro.shtml). Copies of the submission, all subsequent amendments, all 
written statements with respect to the proposed rule

[[Page 97138]]

change that are filed with the Commission, and all written 
communications relating to the proposed rule change between the 
Commission and any person, other than those that may be withheld from 
the public in accordance with the provisions of 5 U.S.C. 552, will be 
available for website viewing and printing in the Commission's Public 
Reference Room, 100 F Street NE, Washington, DC 20549, on official 
business days between the hours of 10 a.m. and 3 p.m. Copies of such 
filing also will be available for inspection and copying at the 
principal office of OCC and on OCC's website at https://www.theocc.com/Company-Information/Documents-and-Archives/By-Laws-and-Rules.
    Do not include personal identifiable information in submissions; 
you should submit only information that you wish to make available 
publicly. We may redact in part or withhold entirely from publication 
submitted material that is obscene or subject to copyright protection. 
All submissions should refer to file number SR-OCC-2024-016 and should 
be submitted on or before December 27, 2024.
---------------------------------------------------------------------------

    \59\ 17 CFR 200.30-3(a)(12).

    For the Commission, by the Division of Trading and Markets, 
pursuant to delegated authority.\59\
Sherry R. Haywood,
Assistant Secretary.
[FR Doc. 2024-28538 Filed 12-5-24; 8:45 am]
BILLING CODE 8011-01-P
```