1177 Avenue of Americas

New York, New York 10036

October 19, 2020

Submitted via CFTC Portal

Mr. Christopher J. Kirkpatrick

Office of the Secretariat

Commodity Futures Trading Commission

Three Lafayette Centre

1155 21st Street, N.W.

Washington, D.C. 20581

Re: TW SEF LLC – Block Trades Guidance 

Dear Mr. Kirkpatrick:

Pursuant to Section 5c(c) of the Commodity Exchange Act (the “Act”) and Section 40.6(a) of the 

regulations of the Commodity Futures Trading Commission (the “Commission”), Tradeweb SEF 

LLC (“TW SEF”) hereby notifies the Commission that it is self-certifying a Market Regulation 

Advisory Notice entitled Notice to All Participants of TW SEF LLC: Block Trades (the “Block 

Trades Notice”). The Block Trades Notice will become effective on November 2, 2020, no fewer 

than ten business days from the date hereof. 

In connection with its submission, TW SEF hereby notifies the Commission that:

1. TW SEF certifies that it has posted the Block Trades Notice on TW SEF’s website and 

has provided this notification to the Commission;

2. TW SEF certifies that the Block Trades Notice complies with the TW SEF Rulebook, the 

Act and the Commission’s regulations; and

3. No substantive opposing views with respect to the Block Trades Notice were expressed 

to TW SEF by its governing board or committee members, members of TW SEF or 

market participants.

This submission letter contains the following attachment:

Attached as Exhibit A is the Blocks Trades Notice, which provides a concise explanation 

and analysis of the operation, purpose, and effect of the Market Regulation Advisory 

Notice and its compliance with applicable provisions of the Act and the Commission's 

regulations thereunder.

Should you have questions regarding this submission, please contact the undersigned at (646) 

560-7223 or at Gregory.compa@tradeweb.com.

Very truly yours,

Gregory Compa

Chief Compliance Officer

TW SEF LLC
EXHIBIT A

TW SEF BLOCK TRADES NOTICE

Effective November 2, 2020

Notice to All Participants of TW SEF LLC:

Block Trades

TW SEF LLC (“TW SEF”) Market Regulation is issuing this notice to remind Participants of the 

requirement to report block trades within the time limits prescribed in TW SEF Rule 411(c)(i). 

Block trades are considered executed when the parties to the trade have agreed on all material 

economic terms (i.e., product, quantity, price). This includes situations in which the parties agree 

to breakdown a larger single order throughout a period of time during the trading day. Where 

there is an agreement as to all material economic terms (i.e., product, quantity, price) for each part 

or piece of the larger single order, each such part or piece is considered an execution. Each such 

agreement to the material terms are a separate execution that requires reporting to TW SEF as 

a block trade. For example, if a Participant contacts another with an interest in trading $500 

million of the current series of 5 year CDX High Yield credit default swap and both Participants 

agree over the course of several hours to five $100 million pieces, each $100 million piece is a 

separate trade and must be reported to TW SEF within the required time frame. The parties to 

these trades shall not report one trade of $500 million at an average price at the end of these 

series of transactions. 

From the time of execution, the parties must report a block trade using TW SEF’s systems “as 

soon as technologically practicable following execution of such Block Trade but no later than 5 

minutes before the time in which such Block Trade would be publicly disseminated by a SDR.” 

If you have any questions concerning these requirements, please reach out to TW SEF Market 

Regulation at Reg.Compliance@tradeweb.com, your TW SEF representative, or our client 

services team at help@tradeweb.com.