In business

Business

A business is an organization engaged in the trade of goods, services, or both to consumers. Businesses are predominant in capitalist economies, where most of them are privately owned and administered to earn profit to increase the wealth of their owners. Businesses may also be not-for-profit...

, the trading day is the time span that a particular stock exchange

Stock exchange

A stock exchange is an entity that provides services for stock brokers and traders to trade stocks, bonds, and other securities. Stock exchanges also provide facilities for issue and redemption of securities and other financial instruments, and capital events including the payment of income and...

 is open. For example, the New York Stock Exchange

New York Stock Exchange

The New York Stock Exchange is a stock exchange located at 11 Wall Street in Lower Manhattan, New York City, USA. It is by far the world's largest stock exchange by market capitalization of its listed companies at 13.39 trillion as of Dec 2010...

 is, as of 2008, open from 9:30 AM Eastern Time

Eastern Time Zone

The Eastern Time Zone of the United States and Canada is a time zone that falls mostly along the east coast of North America. Its UTC time offset is −5 hrs during standard time and −4 hrs during daylight saving time...

 to 4:00 PM Eastern Time

Eastern Time Zone

The Eastern Time Zone of the United States and Canada is a time zone that falls mostly along the east coast of North America. Its UTC time offset is −5 hrs during standard time and −4 hrs during daylight saving time...

. Trading days never take place on weekends. When a trading day ends, all share trading ends and is frozen in time until the next trading day begins. There are several other special circumstances which would lead to a shortened trading day, or no trading day at all, such as on holidays.