SEC and FINRA investor materials describe two kinds of rules: a limit up-limit down (LULD) mechanism with price limit bands for individual stocks, and market-wide circuit breakers that suspend trading across exchanges when they are triggered. A single stock can enter a trading pause that lasts five minutes. A market-wide circuit breaker halts trading on all exchanges. This explainer sets out what each official source states, notes where we are only interpreting, and shows where the evidence stops.
How limit up-limit down price bands work for single stocks
An SEC investor bulletin on circuit breakers states that the price limit bands will be 5%, 10%, 20%, or the lesser of $.15 or 75%, depending on the price of the stock. The bulletin does not give one band for every stock. The band depends on the stock's price.
The same bulletin describes a rollout in two phases:
| Phase | What it covers, per the SEC bulletin | Stated start date |
|---|---|---|
| First phase | All stocks in the S&P 500 and Russell 1000, and select exchange traded products | April 8, 2013 |
| Second phase | All remaining National Market System securities | October 8, 2013 |
The bulletin also gives some history. Single-stock circuit breaker rules first applied only to S&P 500 stocks. They were extended on a pilot basis to all National Market System securities in June 2011.
Our interpretation: The bulletin is written in the future tense ("will be", "will commence"). The claims we reviewed show the planned schedule. They do not confirm whether each phase began exactly on those dates or whether the bands have changed since. Before using these figures, readers should check them against current rule text.
When the LULD rules apply and what they exclude
FINRA's investor guide to market volatility guardrails states two scope points about the LULD Plan:
- Hours: The LULD Plan applies during regular trading hours, from 9:30 a.m. to 4:00 p.m. Eastern Time.
- Exclusions: Rights and warrants are excluded from LULD rules.
The claims reviewed for this article do not list every security type that the plan covers or excludes. They also say nothing about trading outside regular hours beyond the hours stated above. Readers who want the full scope should go to the FINRA material and the plan documents directly instead of reading more into these two points.
How a trading pause works for an individual security
FINRA's guide to volatility guardrails describes how long a trading pause lasts and what can change that length:
- Standard length: A trading pause lasts five minutes.
- Possible extension: The listing market can extend the pause by another five minutes if there is a significant imbalance between buy and sell orders.
- Near the close: If a security is paused during the last 10 minutes of regular trading hours, the primary listing exchange will not reopen trading and will attempt a closing transaction.
The third point means that a pause near the end of the session is handled differently. Instead of reopening trading, the primary listing exchange attempts a closing transaction. FINRA's wording is "attempt," and the claims we reviewed do not say what happens if that attempt fails.
Our interpretation: The claims do not say exactly which price movement starts a pause, or how the price bands described in the SEC bulletin lead to a pause. We don't fill that gap here. To learn how different order types behave in general, see our explainer on market, limit and stop orders. That article does not cover what happens to orders during a pause.
Market-wide circuit breakers: origins and revisions
The SEC press release on the revised market-wide circuit breakers gives the background. It states that the market-wide circuit breakers in place at that time were adopted in October 1988 and had been triggered only once, in 1997.
According to the same press release, in February 2011 the Joint CFTC-SEC Advisory Committee on Emerging Regulatory Issues recommended that the SEC and CFTC review the market-wide circuit breakers.
The press release lists these changes in the revised rules:
- Shorter halts: Trading halts that do not close the market for the day are shortened to 15 minutes, from 30, 60, or 120 minutes.
- Daily thresholds: The trigger thresholds must be recalculated daily rather than quarterly.
The SEC investor bulletin states that the revisions to the market-wide circuit breakers will be implemented on February 4, 2013.
Our interpretation: The press release lists the committee's recommendation and the revised rules together. The claims we reviewed do not say that the recommendation directly caused the revisions, so we don't draw that link. The claims also give no trigger percentages for the market-wide circuit breakers, so this article doesn't state any.
What happens when a market-wide circuit breaker is triggered
FINRA's investor guide states that when a market-wide circuit breaker is triggered, trading is suspended on all exchanges and for listed stocks in the OTC market.
The two kinds of guardrail differ in scope:
| Feature | What the sources state |
|---|---|
| Single-security trading pause | Lasts five minutes, and the listing market can extend it by another five minutes if there is a significant imbalance between buy and sell orders |
| Market-wide circuit breaker | When triggered, trading is suspended on all exchanges and for listed stocks in the OTC market |
| Halt length under the revised market-wide rules | 15 minutes for halts that do not close the market for the day, from 30, 60, or 120 minutes |
The halt length in the last row comes from the SEC press release, not from FINRA.
Where the evidence on circuit breakers and trading halts stops
To keep facts apart from interpretation, here is what the reviewed claims leave open:
- Current status: The SEC investor bulletin and the SEC press release describe planned dates and revisions. The claims don't confirm whether the rules are still the same today.
- Trigger levels: The claims give no percentage-decline levels for market-wide circuit breakers and no exact formula for setting each stock's price band.
- Exact mechanics: FINRA's guide describes how long pauses last and how they are handled near the close. The claims reviewed here do not explain how a pause starts or how trading reopens.
- Effects: None of the claims measures whether these mechanisms reduce volatility or protect investors, and this article makes no such claim.
Anyone who needs current, binding details should read the primary rule documents and the latest material from the SEC and FINRA instead of relying on this summary.
Limits of this article
This article is educational information only. It is not investment, tax or legal advice and does not recommend any product or asset. It does not cover current trigger levels, later rule changes or how any broker handles orders during a halt. It relies only on the cited SEC and FINRA materials.