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​Last Updated: 8/27/2026

#StatusSummaryPosted DateSpec Publish  DateSpec Version Effective Date - TestEffective Date - Prod
1OpenAdd new 'MX2OP' value for the destination, senderIMID and marketCenterID fields to support MX2 Options.3/06/20264/30/20264.2.08/03/20269/14/2026
2OpenAdd new 'IEXOP' value for the destination, senderIMID and marketCenterID fields to support IEX Options.3/06/20264/30/20264.2.08/03/202610/2/2026
3Open

Pursuant to the Commission's order granting Exemptive Relief, dated January 23, 2026, all RFQ responses that are communicated in standard electronic format directly to an Industry Member's OMS/EMS or to an RFQ platform and that are not "immediately actionable" (i.e., further action is required before a trade can be executed/routed), to the extent such responses are considered "orders" reportable pursuant to Rule 613(j)(8), are no longer required to be reported to CAT:

  • Remove MONQ, MORQ, MOQR, MOQC, MOQM, MLNQ, MLRQ, MLQS, MLQR, MLQC, MLQM events
  • Retire bidRelativePrice, askRelativePrice, RFQFlag, validUntilDuration fields
  • Retire Error Codes 2249, 2254, 2255, 2256, and 2257
  • Remove any other related guidance
3/20/20264/30/20264.2.011/23/202612/7/2026

Open

Allow for the exchOriginCode field to be blank/null on MOOR and MLOR events when no value is communicated to exchange. This scenario is currently rejected under Error Code 2028.

8/25/2026

9/25/2026

4.2.0 r2

11/9/2026

12/7/2026

5OpenThe feedbackVersion on all stages of Transaction feedback will change from 4.1.0 to 4.2.0, reflecting the schema version of the specifications and feedback file.8/25/20264/30/20264.2.0

11/9/2026

12/7/2026

*Planned Technical Specification Updates are subject to approval by the CAT NMS Plan Operating Committee.