Proposed Guidance on Marketplace Thresholds and Single-Stock Circuit Breakers

Comments Due By: November 12, 2026

The Canadian Investment Regulatory Organization (CIRO) is proposing to apply volatility controls to extended trading hours. The Guidance on Marketplace Thresholds and the Guidance on Single-Stock Circuit Breakers (together as the Proposed Guidance) have been updated to clarify how these controls would operate outside of core trading hours (i.e. 9:30 a.m. to 4:00 p.m. ET), including periods where there may be limited trading activity. The proposed changes are intended to support consistent application of volatility controls across all marketplaces for which CIRO acts as the regulation services provider, helping to prevent erroneous orders and short-term price volatility and to maintain fair and orderly markets.