Post Mortem: Delayed Reopening for Certain Multi-List Options Classes Following Market-Wide Circuit Breaker

SCI Systems(s) Affected: NBBO Generator

Incident Description: Disruption

Please be advised that Cboe has identified a software defect on the Cboe Options, C2 Options, EDGX Options, and BZX Options exchanges which can result in a subset of multi-list options classes not immediately reopening for trading following today's market-wide circuit breaker event. No proprietary options classes were affected by this issue.

In addition, only on the EDGX Options Exchange, certain additional multi-list classes were inadvertently halted in the process of resolving today's software issue.

Members Affected: Cboe Options Exchange, C2 Options Exchange, EDGX Options Exchange, and BZX Options Exchange customers entering orders in the affected options classes during the affected time period.

Corrective Action: Cboe has implemented a manual procedure to facilitate the reopening of any affected options classes should another market-wide circuit breaker event occur during tomorrow's trading. The underlying software defect will be resolved by a software patch to be deployed to all Cboe options exchange platforms on Wednesday, March 11, 2020.