Revision History

• Minor updates to certification requirement in FIX Port Attributes section.
• Changed AttributedQuote (Tag 9732) ID for retail from "RTL" to "RTAL".

• Removed references to NSX.
• Added OATS EPID section.
• Changed AttributedQuote (Tag 9732) ID for retail from "RETL" to "RTAL".
• Removed highlighting for features where a release date has been announced for BYX Exchange, BZX Exchange and/or Cboe Options.

• Removed highlighting for features where a release date has been announced for BYX Exchange and BZX Exchange.
• Corrected default Price Sliding port attribute setting for EDGX.

• Renamed "Suppress Cancels on Session Close" Port Attribute to "Session Close Handling" and updated options.
• Added support for DoneForDay messages (refer to "Session Close Handling" Port Attribute).
• Removed highlighting for features where a release date has been announced for BYX Exchange, BZX Exchange and/or Cboe Options.
• Added reject code Text (Tag 58) = M: Liquidity Available Exceeds Order Size in support of SWPB.

• Defined "w" cancel reason in Text (FIX Tag 58) field.
• Updated Peg order details to allow for use of displayed Primary pegs.
• Added RoutingInst (Tag 9303) = K.

• ROUC is no longer planned for release on BYX Exchange or BZX Exchange. It will continue to be supported on EDGA Exchange and EDGX Exchange.
• Removed highlighting for features where a release date has been announced for BYX Exchange, BZX Exchange and/or Cboe Options.

• Removed highlighting for features where a release date has been announced for BYX Exchange, BZX Exchange and/or Cboe Options.
• Updated Hours of Operation section to account for new Opening Process on BYX Exchange and BZX Exchange. Effective 12/01/14.

• Deprecated FIX v1 specifications.
• Added v1 messages that continue to be supported (i.e. ExchangeFeeCode tag 9621 and Routing V1 tags).
• TimeInForce (Tag 59) = RHO supported for all symbols on BYX Exchange and BZX Exchange. Effective 12/01/14.
• OrdType (Tag 40) Market implies TimeInForce (Tag 59) of DAY on BYX Exchange and BZX Exchange. Effective 11/14/14.
• Added support for ExecInst (Tag 18) of o=Listing Market Opening on BYX Exchange and BZX Exchange. Available effective 12/03/14.
• Added support for ExecInst (Tag 18) of c=Listing Market Close on BYX Exchange and BZX Exchange. Available effective 12/03/14.
• Added support for ExecInst (Tag 18) of a=Both Listing Market Open and Close on BYX Exchange and BZX Exchange. Available effective 12/03/14.
• Added support for RoutStrategy (v2 Tag 9400) = ROOC on BYX Exchange and BZX Exchange. Available effective 12/03/14.

• Removed restriction that MPM orders must have been sized greater than or equal to an odd lot.
• Added recommended mapping to FIX Tag 851 in TradeLiquidityIndicator (FIX Tag 9730)
• Added "w" and "v" values back to ExecInst (FIX Tag 18) for v1 Routing.
• Updated RoutingInst v2 (FIX Tag 9303) to indicate that Post Only at Limit is supported on BZX and BYX only.

• Added Use Compliance ID to list of FIX Port Attributes.
• Allow for MaxRemovePct (Tag 9618) to be sent with zero value to EDGA and EDGX.

• Added Midpoint Discretionary Order to Order Types and Features section.
• Corrected default sliding values in Re-Priced Orders section.
• Added "CLC" value to ContraBroker (FIX Tag 375).
• Removed reference to legacy Direct Edge FIX Specification.

• Updated description of Unique Wash Execution Ids port attribute.
• Added language to Logon message clarifying behavior around one second wait period after Logon is received.
• Updated RoutingInst v1 (FIX Tag 9303) to add "Z" value back for v1 Routing.

• Clarifications made Discretionary Order and Re-Route Orders in the Order Types and Features section.
• Functionality modifications to EDGX to align with the other Cboe equity exchanges (effective 7/6/15).
• EDGX Midpoint Match translated as Midpoint Peg No Lock (effective 7/6/15).
• EDGX price sliding default changed to Display Price Sliding (effective 7/6/15).
• EDGX and EDGX discretionary order behavior changed to match BZX and BYX (effective 7/6/15)

• Added values to RoutingInst (v1) (FIX Tag 9303), ExDestination (FIX Tag 100), and ContraBroker (FIX Tag 375) in anticipation of NSX reactivation on 8/31/15.
• Added Routing Retail Indicator port attribute (EDGX only). Effective 9/10/15
• Added Single Order ADV Check port attribute. Effective 8/14/15
• Updated description of Fat Finger Protection port attribute.

• Added EffectiveTime (FIX Tag 168).
• Added Duplicative Order Protection port attributes.

• Updated description of ROBB and ROCO RoutStrategy (FIX Tag 9400) values.
• Added Port Attribute "All Routable To Halt Auction". Effective 12/4/15
• Added support for ALL Cboe routing strategy, RoutStrategy (FIX Tag 9400) = ALLB.

• Added Supplemental Peg Order to Order Types and Features section.
• Removed EffectiveTime (FIX Tag 168).
• Updated Stop Order in Order Types and Features to indicate that TimeInForce (FIX Tag 59) is required.
• Cboe branding/logo changes.

• Updated description of Aggressive and Super Aggressive RoutingInst (FIX Tag 9303) values.
• Updated description of Text (FIX Tag 58)
• Update description of RoutStrategy (v2) (FIX Tag 9400) to state routeable ISOs must be sent with "DIRC". Effective 4/25/16

• Additional Cboe branding changes.
• Added three new TimeInForce (FIX Tag 59) values to support addition of Early Trading Session. Effective as early as 5/23/16
• Added Early Trading Session Opt-Out port attribute. Effective as early as 5/23/16
• Updated Hours of Operation. Effective as early as 5/23/16
• Effective Dates by Exchange:

• BYX - 5/23/16
• EDGA - 5/24/16
• BZX - 5/25/16
• EDGX - 5/26/16

• Removed some route strategies.
• Removal of IOCM and ICMT effective May 5, 2016 on BYX Exchange and May 6, 2016 on EDGA Exchange.
• Removal of TRIM3 and TRIM3- effective May 6, 2016 on BZX Exchange.

• Added 4 "Warn %" Port Attributes which are associated with the "Daily Notional Cutoff" Port Attributes.
• Corrected the number of available peg order types.

• Updated Prices section for securities in one of the Tick Size Pilot Program Test Groups. Effective 10/3/16.
• Added Trade At ISO value to ExecInst (FIX Tag 18). Effective 10/3/16.
• Added ExDestination (FIX Tag 100) value for IEX. Effective 8/19/16.
• Added ContraBroker (FIX Tag 375) value for IEX. Effective 8/1/16.

• Removed DE Compatibility Mode References
• Cboe Legacy Routing Mode (RoutingInst v1 ) to be discontinued effective 9/30/16.

• Corrected typo in Logout message.
• Updated DiscretionAmount (FIX Tag 9622) to clarify it is not compatible with Post Only routing instructions.
• Added section 5.14 to describe DIRC to IEX-Midpoint routing
• Added DIRC to IEX-Midpoint value to RoutStrategy
• (FIX Tag 9400).

• Removed references to legacy DROP protocol.
• Added "Port Order Rate Threshold", "Symbol Order Rate Threshold", "Allow Test Symbols Only" and "Allow Directed ISO" Port Attributes.

• Added IEX to the TRIM, TRIM-, TRIM2, and TRIM2- RoutStrategy (FIX Tag 9400).
• Added Non-Displayed Swap (NDS) order. Effective 7/21/17.

• Updated DisplayIndicator (9479) to refer to section 5.4 Peg Orders for applicability of the invisible ‘I’ instruction.
• Updated section 5.4.5 Supplemental Peg Order to eliminate incorrect values.
• Reworked the Order Cancel/Replace Request message to clarify when an order loses time priority and to harmonize with BOE.
• Post to Away orders must be limit orders.

• Updated the market centers that support Post to Away in ExDestination (100).
• Added port attribute "Default True MinQty" (effective 4/18/18).

• Added Cboe Market Close (CMC) functionality (effective TBD).
• Clarified that a zero MaxFloor (111) on an Order Cancel/Replace Request will be ignored.

• LastShares (32) will be used to report the number of shares cancelled on Cboe Market Close restatements.
• CumQty (14) will not report matched shares on CMC restatements and will instead be zero.
• LeavesQty (151) will be used for matched shares on CMC restatements.
• Updated description of Aggressive and Super Aggressive RoutingInst (9303) values.

• Added support for Equities Purge Ports (effective 10/1/18). Added Purge Request, Purge Acknowledgment, and Purge Rejected message types. Added definitions for MassCancelID (7695), MassCancelInst (7700), RiskGroupID (7699), RiskGroupIDCnt (7698), and RiskReset (7692) fields.
• Updated Trading Sessions to reflect that BZX is open until 8:00 p.m. ET.
• MDO ExecInst(18) added to EDGX effective 10/3/18.

• Added note indicating MinQty (110) is not compatible with Retail Price Improving (RPI) orders (BYX Only).
• Sorted table 4.3 numerically by FIX tag.

• Added reason code F=Failed to quote.
• Updated accepted TimeInForce values for Intermarket Sweep Orders to include 1, 4, 5, 6, E, R, T, X.
• Added note to FIX Tag 58 (Text) indicating that the specific text the system delivers may vary from the text listed, to provide clarification of the reject reason.

• Added Cboe Market Close (CMC) functionality effective date - 3/6/20.
• Added ExDestination (100) value of "L" and ContraBroker (375) value of "LTSE" for Long Term Stock Exchange.

• Updated formatting of exchange hours.
• Renamed CustomGroupID field to RiskGroupID.
• Defined new Risk Threshold Warning message that will be added to FIX Drop effective 5/15/20 for EDGA and 5/22/20 for BZX/BYX/EDGX.
• Added Drop Port Attribute "Send Risk Threshold Warnings FIX". (effective May 15)
• Added Port Attribute "Risk Group Id(s)". (effective May 15)

• Added Maximum Open Order Limits section.
• Updated ExecInst (18) with 'e' value to support MDO with QDP and PegDifference (211) to be accepted for MDOs (effective 6/10/20 for EDGA and EDGX Only).

• Updated DisplayIndicator (9479) description.
• Corrected value for 'Intermarket Sweep (Directed or Cboe)' in ExecInst field (18) to lowercase 'f'.

• Updated ROBB and ROCO RoutStrategy (9400) values for EDGA.
• Removed footnote indicating the ExDestination (100) value 'I=Investors Exchange' has the Post to Away option available for ROUT and ROUX.
• Updated Maximum Open Orders Limits to 300,000 for EDGX and BZX.
• Clarifications to usage of PegDifference (211) when using Midpoint Discretionary Orders.

• Added new port attribute 'Hold Early to 7am' (EDGX Only) (effective 03/08/21).
• Updated effective date for changes to EDGX Early Trading Session to 4:00 a.m. and Order Acceptance starting time to 3:30 a.m. (effective 03/08/21).
• Corrected description of TradeLiquidityIndicator (9730) field to include W=Waiting value, as this value is already in use.
• Added ‘Section 1.5.1 - Architecture’ to provide high level overview of protocol architecture and source IP blocking feature.
• Added new ‘Section 1.5.3 - Stale NBBO’ to describe system behavior when SIP NBBO is unavailable.

• Updated the Cboe Holiday Schedule, Exchange Fee Schedule, and Web Portal Port Controls Specification links.
• Added a new Port Attribute "Capacity Override" (effective 10/12/21).

• Corrected description of maximum open order limits to identify that the maximum limit is applicable on FIX ports.
• Duplicative Order Protection Time Threshold to be sunset (effective 12/07/21).
• Duplicative Order Protection Order Count will look at consecutive orders (effective 12/07/21).

• Updated "Port Order Rate Threshold" and "Symbol Order Rate Threshold" Port Attributes to allow a maximum of 10000 msgs/sec (EDGX Only) (effective 12/14/21).
• Added new Port Attributes "Sustained Port Order Rate Threshold" and "Sustained Symbol Order Rate Threshold" (EDGX Only) (effective 12/14/21).

• Updated Duplicative Order Protection Action description.
• Noted IOC Periodic Auction orders will not be accepted (BYX Only) (Effective 04/14/22 TBD).

• Added a new MatchingUnit field to Purge Request messages (Effective 02/11/22 for EDGA and 02/14/22 for BYX, BZX, and EDGX).
• Updated Purge Request section indicating that RiskGroupID (7699) or MPID (115) purges with no Symbol (55) may be directed to a specific matching unit using the MatchingUnit (25017) optional field (Effective 02/11/22 for EDGA and 02/14/22 for BYX, BZX, and EDGX).

• Added PossDupFlag (43) = Y, indicating a message resend and should be used during FIX Replay.
• Noted reject messages will be sent which originate from a FIX order entry session. However, rejects originating from a BOE order entry session will be suppressed.
• Added LocateBroker (5700) to Optional Fields and Execution Report (effective 10/14/22).

• Added PreventMemberMatch (7928) = X indicating prevent match at the affiliate (Exchange Member) level (effective 12/15/22).
• When Default MTP Value port attribute is set to ‘X’, affiliate match trade prevention will be used by default (effective 12/15/22).

• ExecInst = m (Midpoint Peg- No Trade in a Locked Market) will be allowed for PAE orders (CrossTradeFlag = 2) (BYX Only) (effective 03/29/23).
• Added ExDestination (100) = T (pending approval).

• Updated PreventMemberMatch (7928) = X indicating prevent match at the affiliate (Exchange Member) or Sponsored Participant level.
• When "Default MTP Value" port attribute is set to ‘X’, Affiliate Firm’s or Sponsored Participant’s match trade prevention will be used by default.

• Clarified that reserve quantity is replenished when the displayed quantity falls below a round lot.
• Noted a maximum of 1,295 Cancel/Replace requests may be made to a single order each trading day.

• When Default CrossTradeFlag = '2' IOC, FOK, and displayed orders are not converted to a Periodic Auction Eligible order and are sent to the book as-is.
• Added a new CmcSessions (25020) to Cboe Market Close, Cboe Specific Message Fields, New Order Single messages, and Execution Report messages (effective 01/31/25).
• Updated LeavesQty in Execution Report messages to indicate LeavesQty may include shares already matched in an earlier session for CMC restatments.
• Updated LeavesQty in CMC section to indicate that LeavesQty is the quantity of unexecuted shares.
• Added a new CmcMatchQty (25023) to Cboe Market Close, Cboe Specific Message Fields, and to Execution Report messages (effective 01/31/25).

Updated with Cboe Titanium branding.

Updated CmcSessions (25020) to clarify that S = 3:54 p.m. (NASDAQ-listed only) in New Order Single messages (effective 01/31/25).

Updated CmcSessions description in the Cboe Market Close section (effective 01/31/25).

• Added updated BZX times in trading session and added BZX to Hold Early to 7am Port Attribute (effective 05/01/25).
• Noted when the normal repricing of a Market Maker peg order to the designated percentage would result in the order being priced in excess of the system limitation of $999,999.99, the system limitation will prevail.

• Added Microsecond Timestamp Granularity to FIX Drop Port Attributes.

• Added LocateBroker (FIX Tag 5700) to the Order Cancel/Replace message.
• Added new "Enforce Rate Limit via Pause" Port Attribute (effective 06/27/25).

• Updated ContraBroker to indicate that CHX = Routed to NYSE Texas
• Updated ExDestination to indicate that M = NYSE Texas.

• Added G = 24X to ExDestination (100) in New Order Single Message Fields.
• Added TFXE=Routed to 24X to ContraBroker (375) in Execution Report Messages Fields.

• Updated ExDestination (100) in New Order Single Message Fields to indicate that G = 24X National Exchange
• Updated ContraBroker (375) in Execution Report Messages Fields to indicate that TFXE = Routed to 24X National Exchange

• Added the StepUpAmount field to Cboe Specific Message Fields, New Order Single Message Fields, and Execution Report Message Fields (effective 01/30/26).
• Updated Retail Price Improving (RPI) Orders to include Enhanced RPI orders.

Added "Send Nanoseconds" port attribute to FIX Port Attributes and FIX Drop Port Attributes (effective 03/27/26).

Updated OrigTime and TransactTime fields to indicate that GMT date-time of the original trade will be available in nanoseconds (effective 03/27/26).

• Updated PegDifference (211) and ExtendedExecInst (9416) in New Order Single Message Fields to indicate RPI will apply to both BYX and EDGX (effective 04/10/26).
• Updated MinQty (11) in New Order Single Message Fields to indicate it is not compatible with Retail Price Improving (RPI) orders (BYX and effective 04/10/26 EDGX Only).
• Updated TradeLiquidityIndicator (9730) in Execution Report Message Fields to indicate 2nd character value E will apply to both BYX and effective 04/10/26 EDGX.
• Updated Retail Price Improvement Program to indicate RPI will apply to BYX and effective 04/10/26 EDGX.
• Updated "Retail Order - Type 2 - Book Only" and "Retail Order - Type 2 - Routable" details in Retail Orders (ROs) (effective 04/10/26).
• Updated Retail Price Improving (RPI) Orders to indicate RPI will apply to both BYX and EDGX and updated "Retail Price Improving Peg order" details (effective 04/10/26).
• Removed Trading Sessions table from Hours of Operations and added a link to the trading hours on the Cboe website.
• Added ResetSeqNumFlag (FIX Tag 141) to Logon Message Fields and clarified its use during Logon for emergency sequence number re-initialization.

• Updated the product and session trading hours link in Hours of Operation.
• Added ContraBroker and ExDestination values for Texas Stock Exchange.

• Pegged orders entered without a Price (44) are only accepted during RTH (effective 12/07/26).
• Updated TimeInForce language for EDGX 23x5 trading (effective 12/07/26).
• "Early Trading Session Opt-out" and "Hold Early to 7am" port attributes will be sunset 12/07/26.
• Added new "Hold Early Orders Until" port attribute (effective 12/07/26).

• Added DisplayIndicator (FIX Tag 9479) value of h = Hidden Multiple Price Slide (effective 09/04/26).
• Added DisplayIndicator to Intermarket Sweep Order (ISO).
• Added Hidden Multiple Price Slide to Re-Priced Orders (effective 09/04/26).