Cboe Exchange adopts related-group framework for complex order legging and risk limits

On October 9, 2026, Cboe Exchange, Inc. filed a proposed rule change with the Securities and Exchange Commission that became immediately effective, as noted in Release No. 34-106696, File No. SR-CBOE-2026-081 (FR Doc No. 2026-21576). The filing solicits comments through the standard SEC notice-and-comment process.

The amendment to Rule 5.33(g) adds a related-group provision permitting a complex order whose legs reside in different series groups - provided Cboe designates those groups as related - to leg into the Simple Book as well as be posted to the Complex Order Book. This expands the current restriction that bars legging when groups are listed on a group basis under Rule 4.13(f).

A concurrent amendment to Rule 5.34 introduces interpretive guidance allowing the Exchange, and where applicable its Users, to set risk-control parameters on a related-group basis. Under the new language, trading limits such as notional value or contract count may be aggregated across groups that share a matching engine, rather than being applied separately to each group.

In practice, Cboe will designate SPX and the newly launched weekly A.M.-settled SPX options (SPXO) as a related group because both reside on the same matching engine. Complex orders that combine SPX and SPXO legs will therefore be eligible to leg into their respective Simple Books, and risk limits for a user will be aggregated across the two series. By contrast, SPXW options remain on a separate engine and will continue to be treated as an independent group.

The text of the proposed rule change and related statements are available on the SEC's website, Cboe's website, and at Cboe's principal office. Interested parties may submit comments as prescribed in the notice.