Short Sale Restriction (SSR) is an SEC rule that kicks in automatically when a stock drops 10% or more from the previous day's close. It's a circuit breaker under Regulation SHO that forces short sellers to wait for an uptick instead of hitting the bid.
It's officially SEC Rule 201, also called the alternative uptick rule. The SEC introduced it in 2010 after the 2008 financial crisis, replacing the original uptick rule that had been repealed three years earlier.
When does SSR trigger and how long does it last?
SSR activates the moment a stock falls 10% from the prior session's close on a national securities exchange. Once triggered, it stays active for:
The rest of that single trading session, and
The entire next trading day
So a stock that tanks Tuesday afternoon stays SSR'd through Wednesday's close.
How does SSR actually work?
To short an SSR name, your order has to sit above the national best bid — effectively, a limit order placed above the inside bid that waits for an uptick to fill. No more slamming the bid at market.
The rule exists to stop short sellers from piling on and accelerating a sharp decline. SSR doesn't affect long positions, options trading, or most market maker activity — it only restricts the short sale of the underlying stock.
How does SSR affect a stock's price?
SSR often fuels squeezes.
When shorts can't aggressively hit the bid, downward momentum stalls out. A stock that looked dead can rip 20–30% on panic covers — especially when hedge funds and active short sellers are caught with heavy short positions. That's why experienced retail traders scan the SSR list every morning. Those names have built-in squeeze potential.