The Bombay Stock Exchange (BSE) (formerly, The Stock Exchange, Bombay) today completes 140 years of its existence. Asia's oldest stock exchange started under a tree on 9th July, 1873. BSE is a stock exchange located on Dalal Street, Mumbai and is the oldest stock exchange in Asia. The equity market capitalization of the companies listed on the BSE was US$1 trillion as of December 2011, making it the 6th largest stock exchange in Asia and the 14th largest in the world. The BSE has the largest number of listed companies in the world.
 
As of March 2012, there are over 5,133 listed Indian companies and over 8,196 scrips on the stock exchange, the BSE has a significant trading volume. The BSE SENSEX, also called "BSE 30", is a widely used market index in India and Asia.
 
BSE traces its history to the 1850s, when four Gujarati and one Parsi stockbroker would gather under banyan trees in front of Mumbai's Town Hall. The location of these meetings changed many times, as the number of brokers constantly increased. The group eventually moved to Dalal Street in 1874 and in 1875 became an official organization known as 'The Native Share & Stock Brokers Association'.
 
In 1956, the BSE became the first stock exchange to be recognized by the Indian Government under the Securities Contracts Regulation Act. The BSE developed the SENSEX in 1986. In 2000 the BSE used this index to open its derivatives market, trading SENSEX futures contracts. The development of SENSEX options along with equity derivatives followed in 2001 and 2002.
 
BSE switched to an electronic trading system in 1995. It took the exchange only 50 days to make this transition.
 
Following is the timeline of the BSE