There are different procedures and codes in place for trading halts across different markets. Let’s take a look at some of the most popular global exchanges and their trading halt processes.
Nasdaq trading halts
When trading halts occur on the Nasdaq, several halt codes are used to tell traders why the action was taken. Here are some of the most common:
- T1 – trading is halted pending the release of significant (or material) news
- T2 – trading is halted to allow for investors to assimilate news released
- T5 – there is a single stock pause due to a 10% or more price change in a security within a five-minute period
See the full list of Nasdaq trading halt and suspension codes.
The SEC also has a Limit Up-Limit Down (LULD) rule, which halts activity if a stock is trading outside of its specified price bands. These are established at a percentage level above and below the average price of a security over the immediately preceding 5-minute period.
NYSE trading halts
The New York Stock Exchange has similar codes to inform traders as to the reason for the halt. These are:
- News pending
- News dissemination
- Regulatory concern
- Limit Up-Limit Down (LULD)
See the current NYSE trading halts.
ASX trading halts
On the Australian Securities Exchange (ASX) trading halts can be put in place by the exchange or requested by a company. Securities are placed into a 'Trading Halt Session State' and will have the code ‘TH’.
The ASX lifts the trading halt after the release of the announcement, so normally the stock isn’t available until the close of business on the following day. A trading halt on the ASX cannot last longer than two trading days.
LSE trading halts
The London Stock Exchange uses trading halts far more sparingly than other exchanges, preferring to use circuit breakers instead. But it does reserve the right to impose a temporary trading suspension or trading halt for a particular market, segment or tradable instrument as market situations dictate.
For example, in early 2022, the LSE halted trading on Russian securities, including Gazprom, EN+ and Sberbank, as part of sanctions in connection with the invasion of Ukraine.
CME trading halts
Short outages on the CME often originate from its ‘Velocity Logic’, which tends to kick in around major data releases from the US.
Longer-term outages are likely to be after more significant price moves cause price limits to be hit. These price limits are set on index and commodity futures contracts each trading session. When a market hits this price limit, different actions can occur depending on the market in question. The main consequences are:
- Trading halts until the price limits expand
- Trading remains in the limit condition
- Trading stops for the day
You can find the daily price limits for each commodity market on the CME Group website.