A trading halt is a temporary suspension of trading for a particular security or securities at one exchange or across numerous exchanges. Trading can be halted in anticipation of a news announcement, to correct an order imbalance, as a result of a technical glitch, due to regulatory concerns or because the price of the security or an index has moved rapidly enough to trigger a halt based on exchange rules. When a trading halt is in effect, open orders may be canceled and options still may be exercised.