Effective April 3, 2025 on EDGX Options Exchange, and effective April 7, 2025 on Cboe Options (C1), Cboe C2 Options, and BZX Options Exchanges, subject to regulatory review, Cboe will introduce wide market protection (WMP) functionality to reduce the risk of orders executing at adverse prices.

WMP will be initiated when an incoming market order, limit order, or elected stop/stop limit order is received into the book while the NBBO is deemed wide. Protected orders will be displayed and worked in the book at an initial benchmark price and iterate to progressively more aggressive levels, up to their limit.

WMP will be disabled 30 seconds prior to the close of the regular trading hours (RTH) and Curb sessions (as applicable).

WMP will initiate a pause on inbound market orders, limit orders, or elected stop/stop limit orders when the NBBO is deemed “wide” based on pre-established configurable parameters. Specifically, the NBBO is considered wide if the bid/ask spread is wider than the Wide Market Protection Determinant based on the NBB (Bid Price) in Table 1 below. The WMP Determinants are purposely set tighter than Obvious Error levels, which are also provided for convenience.

Cboe will initiate WMP upon the following events:

• A limit or market order is received when the NBBO is deemed wide.
• A stop or stop limit order is triggered and the NBBO after the triggering event is deemed wide.