Single stock circuit breakers

Learn what single stock circuit breakers are and how they can affect you.

Single stock circuit breakers ("SSCBs") (opens in a new tab)

, are tools used by stock exchanges to prevent large, sudden price moves in a stock and/or extraordinary market volatility. When a SSCB is triggered, there is an initial trading halt of five minutes for the applicable security, which may be extended for a further five-minute period at CIRO’s discretion. 

In Canada, an SSCB for Qualifying Securities (opens in a new tab) (except Leveraged ETFs) is triggered in the event of a price increase or decrease of (one of the following): 

• At least 10% and 20 trading increments (the price interval at which an order may be submitted and traded) in a five-minute period between 9:50 a.m. and 3:30 p.m.

• At least 20% and 40 trading increments in a five-minute period between 9:30 a.m. and 9:50 a.m.

• At least 20% and 40 trading increments in a five-minute period during the 30-minute period following the resumption of trading after a regulatory halt, including a regulatory halt caused by the triggering of a SSCB.

For Leveraged ETFs, trigger levels are calculated by multiplying the trigger levels for qualifying securities with the leverage ratio of the Leveraged ETF. For example, a qualifying Leveraged ETF with a 2:1 ratio will have trigger levels set at twice the usual level of a qualifying non-Leveraged ETF.

In the US, SSCBs are more commonly known as

limit-up/limit-down (opens in a new tab)

(“LULD”). To learn more about how LULD work in US markets you can read this article from

Nasdaq (opens in a new tab)

.