Short-Sale Rule
The short-sale rule refers to price-test restrictions on short sales, including the former uptick rule and current Regulation SHO Rule 201 circuit breaker.
The short-sale rule refers to U.S. price-test restrictions that limit when certain short sale orders may be executed. Historically, it often means the old SEC uptick rule, former Rule 10a-1. In current U.S. equity-market discussion, it usually points to Regulation SHO Rule 201, the short-sale price-test circuit breaker.
The rule is not a general ban on Short Selling. It is a trading-center and order-handling rule that can restrict short sales at or below the national best bid after a covered security has experienced a large intraday price decline. This page is educational and is not legal, compliance, or trading advice.
Key Takeaways
- The old uptick rule, former SEC Rule 10a-1, applied a price test to exchange-listed short sales for decades before it was removed in 2007.
- The current U.S. short-sale price-test framework is Regulation SHO Rule 201, often called the alternative uptick rule or short-sale circuit breaker.
- Rule 201 is triggered when a covered security declines by 10% or more from the prior day’s closing price, as determined by the listing market.
- Once triggered, the price-test restriction generally applies for the rest of that day and the following day, unless an exception applies.
- The rule affects order display and execution mechanics; it does not remove borrow, Locate, margin, or settlement obligations.
Old Uptick Rule vs Current Rule 201
| Feature | Former Rule 10a-1 uptick rule | Regulation SHO Rule 201 |
|---|---|---|
| Basic idea | Restrict short sales based on the last sale price tick | Restrict short sales after a covered security has a large intraday decline |
| Trigger | Applied as a general price test to covered exchange-listed short sales | Triggered by a 10% or greater decline from the prior day’s closing price |
| Price reference | Last sale price and tick direction | National best bid after the circuit breaker is triggered |
| Status | Removed by the SEC in 2007 | Current Regulation SHO price-test circuit breaker |
| Practical focus | Historical short-sale price test | Current order-handling, routing, display, and compliance controls |
How Rule 201 Works In Practice
Rule 201 is best understood as a workflow for trading centers and broker-dealers, not as a simple trading signal.
| Step | What happens | Why it matters |
|---|---|---|
| Prior close is set | The listing market determines the prior day’s closing price | This is the reference price for the 10% trigger |
| Intraday decline occurs | The security falls by 10% or more from that reference price | The Rule 201 circuit breaker is triggered |
| Price-test restriction applies | Short sale orders generally cannot be executed or displayed at an impermissible price | Traders may need different limit prices, routing, or timing |
| Restriction period continues | The restriction generally remains for the rest of the day and the following day | The effect can outlast the initial price drop |
| Exceptions are reviewed | Some orders may be marked short exempt if an exception applies | The exception needs evidence, not just a trader preference |
Simple Example
Assume a stock closed yesterday at $100. During today’s regular trading session, it falls to $90. That 10% decline can trigger the Rule 201 short-sale price-test restriction.
After the trigger, a short sale order generally cannot be executed or displayed at a price that is equal to or below the current national best bid, unless an exception applies. A trader may still be able to short the stock at a permissible price, but the order must fit the rule, broker procedures, locate requirements, margin rules, and market liquidity.
Common Mistakes
- Treating the short-sale rule as a full ban on short selling.
- Assuming Rule 201 applies all the time rather than after the circuit breaker is triggered.
- Confusing the old uptick rule with current Rule 201 mechanics.
- Ignoring order marking, short-exempt status, and trading-center responsibilities.
- Treating a triggered short-sale restriction as proof that a stock is manipulated.
- Forgetting that price-test rules are separate from Naked Short Selling, fail-to-deliver, locate, and close-out analysis.
What To Verify
Short-sale-rule analysis should be tied to the market record because the answer depends on time, venue, price, security type, and order handling.
| Question | Evidence to check |
|---|---|
| Did the security trigger Rule 201? | Prior close, listing-market trigger notice, price history, and timestamp |
| Was the order a short sale or short exempt? | Order ticket, order marking, exception code, and supervisory record |
| Was the price permissible? | National best bid, limit price, routing record, and execution report |
| Was the restriction still in effect? | Trigger date, following-day window, exception status, and trading session |
| Did locate and settlement obligations still apply? | Locate record, borrow source, settlement status, and close-out file |
Public Source Checks
- SEC: Key Points About Regulation SHO
- SEC: Rule 201 of Regulation SHO FAQ
- SEC: Short Sale Price Test Restrictions compliance guide
- SEC: Regulation SHO and Rule 10a-1
These public sources provide U.S. rule context. They do not determine whether a specific order, short-exempt marking, trading-center policy, route, or execution report complied with the rule.
Related Terms
- Short Sale: The transaction that sells borrowed securities.
- Short Selling: Broader practice of using short sales for exposure, hedging, liquidity, or strategy.
- Locates: Documented pre-trade checks that shares can reasonably be borrowed and delivered.
- Naked Short Selling: Short-sale activity without arranging borrow in time for delivery.
- Going Short: Creating exposure that generally benefits if the market price falls.
- Regulation SHO: SEC short-sale rule framework covering marking, price-test, locate, and close-out requirements.