Ratios for Combo Orders

Non-FLEX Index combo orders are eligible for COA, COB, and AIM.

A combo is defined as any pair of legs buying a call and selling a put (or vice-versa) with the same strike and expiration in a 1:1 ratio. Orders with more than one option leg plus a combo will qualify for trading.

Automated handling for Index Combo orders includes orders with multiple combos. To determine the ratio, the System compares the smallest non-combo leg versus the quantity on the smallest combo.

Additionally, Index Combo orders executed in open outcry qualify as complex orders and will be afforded benefits applicable to other conforming complex orders.

Automated handling via COA, COB, AIM, QCC (C1 and EDGX only), and C-SAM (C1 and EDGX only) is available for applicable non-conforming orders, except in SPX/SPXW/SPXO* (C1 only). Automated handling of SPX/SPXW/SPXO* non-conforming spreads is enabled in GTH, including via COA, COB, and AIM.

All FLEX Option classes (including SPX/SPXW/SPXO*) also allow automated handling of non-conforming complex orders.

*Effective 11/09/26