Regulatory and non-regulatory trading halts Both
Post# of 96879
Both of the reasons mentioned above are "regulatory" trading halts and are implemented on many major stock exchanges (for example, the American Stock Exchange, NASDAQ, and New York Stock Exchange). When a United States exchange enacts a regulatory halt for a security, other U.S. exchanges that also trade the security will honor the halt.[1]
The NASDAQ and other exchanges currently use 11 codes to specify in more detail why trading has been halted for a security.[2] The Over The Counter Bulletin Board (OTCBB) currently uses 5 codes.[3]
A "non-regulatory" trading halt occurs if "significant order imbalance between buyers and sellers in a security" exist. (The NASDAQ stock exchange does not implement non-regulatory trading halts.) Before trading resumes, market specialists must determine an appropriate price range in which the security can trade. Unlike regulatory halts, other U.S. exchanges do not always stop trading a security affected by the non-regulatory halt.[1]
NASDAQ OMX (owner of the NASDAQ stock market) displays current trading halts for the NASDAQ, New York Stock Exchange, and the American Stock Exchange, along with a rolling 21-day history. The OTCBB maintains its own trading halt list and a rolling 6-month history.