Cboe Adds Stop-Limit Orders and SCOA Auction Type
Published Date: 3/26/2026
Notice
Summary
Cboe Exchange is updating its rules to let traders use stop-limit complex orders and is launching a brand-new auction type called Stop Complex Order Auctions (SCOA). This change helps traders manage complex trades better and could speed up how these orders get matched. The new rules kick in soon and might impact trading strategies and costs for anyone using complex options on Cboe.
Analyzed Economic Effects
8 provisions identified: 6 benefits, 0 costs, 2 mixed.
Stop‑Limit Complex Orders Allowed
If you trade complex options on Cboe, the Exchange will accept “stop‑limit complex orders” so a single order for two or more option legs can become a limit order when a designated trigger condition is met. This extends existing stop‑limit functionality (previously for simple orders only) to complex option strategies.
New SCOA Auction Mechanism
Cboe will run a new auction type called a Stop Complex Order Auction (SCOA) that will process triggered stop‑limit complex orders. SCOA bundles multiple stop‑limit complex orders that share the same trigger event to maximize executed quantity and pursue price improvement, and stop‑limit complex orders will be processed only via SCOA (not COA).
Market‑Maker SBBO Trigger Protection
One trigger for stop‑limit complex orders uses a new “Market‑Maker SBBO” (best bid and offer calculated using only appointed Market‑Maker quotes) so stop triggers do not fire because of non‑Market‑Maker single‑leg customer orders. This is intended to reduce inappropriate cascades of triggered stop orders.
Who Can Respond to SCOA
The Exchange will determine class‑by‑class whether all Users may submit SCOA Auction Responses or whether only Market‑Makers with appointments and certain Trading Permit Holders (TPHs) acting as agent for orders at the top of the COB may respond. SCOA messages will be sent to recipients of auction messaging data.
Risk Controls and Optional SCOA Volume Exclusion
Users may specify whether SCOA volume or executions count toward a User's class, EFID, or EFID Group risk limits; option volume from SCOA may be excluded from certain risk monitor parameters. This setting is optional and under user control.
Early Termination & Anti‑Manipulation Protections
SCOA may terminate early if orders in a leg improve or join the SBBO in ways described in the rules. The Exchange added SCOA to an interpretation so that a pattern of order submissions by a TPH that causes early SCOA termination can be treated as conduct inconsistent with just and equitable principles of trade and a violation of Rule 8.1.
SCOA Response Time Limit
The Exchange will set SCOA Response Time Intervals on a class‑by‑class basis and the duration may not exceed 1000 milliseconds (1,000 ms). During this interval, auction responses may be modified or withdrawn; at interval end, responses become firm.
Post‑Auction Handling and Iterations
If SCOA does not fully fill orders, unfilled portions will be entered into the Complex Order Book (COB) if eligible, and the System will run iterations with incrementally more aggressive starting prices until filled, the limit price is reached, or the opposite‑side SBBO is used as the last auction start price.
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