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US Equities BOE Port Attributes

The table below lists BOE port attributes that are configurable on the port or firm level. Changes to these attributes can be made by contacting the Cboe Trade Desk.

Table 1. US Equities BOE Port Attributes
AttributeDefaultDescription
All Routable to Halt Auction (BZX and EDGX Only)NoSend all routable orders to the halt auction on the primary listing exchange. This applies to all routing strategies.
Allow Directed ISO1YesAllow or disallow ISO orders directed to other market centers.
Allow ISO1YesAllow or disallow ISO orders.
Allow MTP Decrement Override1,3NoOverrides the exception that requires both the resting and inbound order to be marked as Decrement.
Allow Post-MarketYesAllow orders to be entered after the Regular Session close.
Allow Pre-MarketYesAllow orders to be entered prior to Regular Session open.
Allow Sponsored Participant MTP Control1,3NoAllow Sponsored Participant to override port default for match trade prevention by using PreventMatch on the order level.
Allow Test Symbols OnlyDisabledAllow or disallow orders in non-test symbols.
Allowed Clearing MPIDs1All MPIDs
  • MPID(s) allowed for trading on the port.
  • If Sponsored Port attribute is enabled, only one Clearing MPID is allowed for trading on that port.
Cancel on DisconnectOption 1
  • Cancels open orders upon order handler session disconnect; both graceful and ungraceful. If Cancel On Disconnect is set, open orders in Symbols that are not in Closed state at the time of the disconnect are cancelled.
  • 1 = Cancel continuous book orders only (default)
  • 2 = Cancel all open orders (continuous + auction)*
  • 3 = Do not cancel any open orders
  • *If disconnect occurs during the cut-off period for an auction, On-Open, On-Close and Late orders that are to participate in the auction will not be cancelled.
Cancel on ME DisconnectYesWhen set to No, this setting allows orders to remain open on a Matching Unit failover. When set to Yes, all open orders associated with a session are immediately cancelled in the event of loss of connectivity to a Matching Unit. In any event, if a failover takes longer than five minutes, all orders are cancelled unconditionally.
Cancel on Regulatory HaltNoCancels open orders upon receipt of a Regulatory Halt.
Cancel on Reject 2NoCancels an order upon a modify reject.
Cancel Open Orders on DROP Port Disconnect1None
  • Only applicable if Reject Orders on DROP Port Disconnect has been enabled. When the last Standard FIX DROP port associated with an order handler session has disconnected, open orders, associated with the session are cancelled.
  • No = Disabled
  • Yes = Cancel all open orders
  • Note this parameter applies to Standard FIX DROP ports and not Order-By-Order DROP ports (ODROP).
Capacity OverrideNone
  • When set, the capacity of individual orders received on the port will default to the Member specified order capacity.
  • None = No override (default)
  • A = Agency
  • P = Principal
  • R = Riskless Principal
Crossed Market Cancel / RejectNoReject new orders when the NBBO in the security is crossed. Routable orders will have any remaining quantity cancelled back when the order returns to the book. Order modifications which cause a loss in priority will result in a cancel of the original order if the NBBO is crossed upon receipt of the modify request.
Default Attributed Quote 1,2(see description)
  • Default value for AttributedQuote (9732). May override at order level.
  • Yes = Attribute to MPID
  • RTAL = Attribute as RTAL
  • No = Don’t Attribute (may override at order level)
  • Never = Never Attribute*
  • *May only change this setting to Yes or No after executing Attribution Addendum to Exchange User Agreement.
Default CrossTradeFlag (BYX Only) 1,20
  • Sets default CrossTradeFlag for inbound orders to designate Periodic Auction eligibility.
  • 0 = None (default)
  • 1 = Periodic Auction Only
  • 2 = Periodic Auction Eligible
  • 3 = Midpoint Peg - Periodic Auction Only
  • When set to 2:
  • IOC, FOK, and displayed orders are not converted to a Periodic Auction Eligible order and are sent to the book as-is.
  • DisplayIndicator (9479) will be ignored if ExecInst (18) = m or M.
  • When set to 3:
  • IOC, FOK, IOC/FOK orders with ExecInst (18) = M, and all other orders where ExecInst (18) != m will not be converted and will be sent to the book as-is.
  • All non-IOC/FOK orders with ExecInst (18) = M will be converted to RHO Midpoint Peg - Periodic Auction Only order.
  • Orders with the following RPI instructions will set this port attribute to 0:
  • ExtendedExecInst (9416) = R or P, plus is an IOC
  • ExtendedExecInst = T
Default Exec Instruction 1,2(None)Default execution instruction for new orders. See ExecInst for details. If a port level setting is present, new orders sent with a value of NULL 0x00 will use the port level setting.
Default MPIDNoneDefault MPID to use if none is sent on a New Order message.
Default MTP Value1,2,3NoneSpecifies default value for PreventMatch. When set to X, Affiliate Firm’s or Sponsored Participant’s match trade prevention will be used by default.
Default Price Sliding(Hidden Order Override)2SDefault price sliding behavior for hidden orders. See DisplayIndicator for details.
Default Price Sliding 2SDefault price sliding behavior. See DisplayIndicator for details.
Default Routing Instruction (Hidden Order Override)2Specifies a default value for RoutingInst that is applied to hidden orders only.
Default Routing Instruction2Specifies a default value for routing. Fields can be overridden at the order level. The defaults are RoutingInst = R, RouteDeliveryMethod = RTI, and RoutStrategy = ROUT
Default to Retail Order1,2,3NoneDefault ExtExecInst = R or P
Default True MinQtyNo
  • Do not aggregate multiple contra orders to meet the MinQty specified on an order.
  • If set to Yes, orders will be converted into standard MinQty during a Periodic Auction. Periodic Auction Eligible orders will remain as True MinQty in the continuous book (BYX Only).
Disallow Market OrdersOption 1
  • Controls the acceptance or rejection of inbound Market orders during continuous trading.
  • 1 = Do not restrict Market orders
  • 2 = Reject Market orders during continuous trading,but allow Market orders during openings, re-openings, auctions, and auction routing (e.g. ROOC)
  • 3 = Reject all Market orders except MOO and MOC orders (including CMC orders)
Duplicative Order Protection ActionOption 1
  • Action taken when Duplicative Order Protection criteria is met:
  • 1 = Not enabled
  • 2 = Reject new offending orders
  • 3 = Disable port for ClearingFirm. Must call Cboe Trade Desk to reenable.
Duplicative Order Protection Order Count ThresholdNoneNumber of consecutive orders with the same ClearingFirm, Price, OrdQty, and Symbol that must be seen to initiate Duplicative Order Protection Action.
Early Trading Session Opt-Out ​ (Sunset Effective 12/07/26) ​No
  • Allows orders to be executable during the Early Trading Session. If set to Yes, the following TimeInForce values will be translated:
  • 0 (DAY) → E (PRE)
  • 5 (GTX) → X (PTX)
  • 6 (GTD) → T (PTD)
Enforce Rate Limit via PauseFalse
  • When set to False, the existing Port Order Rate Threshold, Sustained Port Order Rate Threshold, Symbol Order Rate Threshold, and Sustained Symbol Order Rate Threshold port attributes will be enforced by rejects (as described).
  • When set to True, Port Order Rate Threshold, Sustained Port Order Rate Threshold, Symbol Order Rate Threshold, and Sustained Symbol Order Rate Threshold port attributes will be enforced by read pause instead of by rejects.
Fat Finger Protection1None
Force MDO with QDP (EDGA and EDGX Only)n
  • When set, midpoint and standard MDO order types will default to MDO with QDP orders.
  • n = Do nothing (default)
  • b = Book only MDO with QDP
  • p = Post only MDO with QDP
Hold Early Orders Until (BZX and EDGX Only) (Effective 12/07/26)FalseIf configured, the system will use the later of the start time specified here or the start time of the TimeInForce value specified on the order. Start times may be set in 1/2 hour increments up to 9:00 a.m. ET.
Hold Early to 7am (BZX and EDGX Only) (Sunset Effective 12/07/26)False
  • Controls the executable time of orders submitted prior to 7:00 a.m. ET with a TimeInForce (59) that allows trading in the Early Trading Session.
  • False = Orders may enter the book and trade as early as 4:00 a.m. ET.
  • True = Orders will be queued until 7:00 a.m. ET.
Lock Auction Orders (BYX Only)False
  • Disallow order cancellation during periodic auction.
  • False = Allow cancellations
  • True = Do not allow cancellations
Maximum Order Dollar Value1UnlimitedMaximum dollar value per order.
Maximum Order Size125,000Maximum order quantity
MPID Filter for Purge PortsNoneSpecify up to 10 EFIDs per purge port for which purges will be permitted. If a purge request (with first character of MassCancelInst =F) specifies an EFID not included in the list of configured EFIDs, the purge request will be rejected. If a purge port is configured with multiple EFIDs and a purge request is sent (with first character of MassCancelInst = A) without any EFIDs specified, the purge will be applied only to the list of configured EFIDs.
Port Order Rate Threshold5,000 msgs/s
  • The maximum allowed message rate on the session. When the first non-session level message is received, a one second window begins. During the second no more than 4,999 additional non-session level messages will be allowed within that window. If the rate is exceeded, all new orders in the time window are rejected, modifies are treated as cancels, and cancels are processed.
  • Note: Order handler burst rates towards each matching unit may be limited as described in Architecture and Message in Flight Settings.
Reject Market Orders Without NBBONoReject Market Orders (including unpriced Peg Orders and Stop Orders) when there is no NBBO on the opposite side.
Reject Orders on DROP Port Disconnect1No
  • If all associated Standard FIX DROP ports associated with an order entry session experience disconnection, new orders will be rejected until at least one Standard FIX DROP port session has been reestablished.
  • Note this parameter does not apply to Order-By-Order drop ports (ODROP).
Reject Orders on DROP Port Timeout (seconds)130 seconds
  • Only applicable if Reject Orders on DROP Port Disconnect has been enabled. When the last Standard FIX DROP port associated with an order entry session has disconnected, begin rejecting orders on the order entry session if a Standard FIX DROP session has not been reestablished within this timeout.
  • Minimum value allowed is 0 seconds.
Risk Group Id(s)NoA comma separated list of values that, if configured, will cause orders without one of the listed RiskGroupIDs to be rejected.
Routing Retail Indicator (EDGX Only)NoMark orders as retail when routing to dark liquiditypools.
Send All Local Rejects1No
  • Make all order, cancel, and modify rejects available via ODROP. By default, some rejects are discarded if they would violate the port rate limit.
  • Note: choosing true for this attribute will enforce a hard 6,000 requests per second limit that is enforced by a read pause on this port.
Single Order ADV CheckNoneReject orders when order size exceeds a specified percentage of the 20-day ADV. Members may also specify a 20-day ADV amount below which the check will not be applied.
Sponsored PortNoDesignates that the session will carry Sponsored flow.
Sponsoree Firm IDNoneOnly available when Sponsored Port is set to Yes. Will be populated with the Sponsored Firm's Firm ID.

1Sponsored Participants require written approval from Sponsors to update these settings on ports associated to a Sponsor’s MPID.

2Port attribute can be overridden on an order by order basis.

3Requires certification.

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