What is a trading halt?

During a trading halt the market freezes the trading of a particular stock. This can happen for multiple reasons like: news announcements from the company, or regulatory reasons or if they detect something suspicious concerning the stock prices. During this period only open orders can be canceled or options exercised. The trading halt gives the investors an opportunity to evaluate the new information from the company and decide to sell or buy or to hold. Usually a trading halt lasts around thirty minutes and transactions will continue on after it is over.