Twitter shares jump on market debut
7 November 2013 Last updated at 17:50 GMT
Shares in Twitter opened at $45.10 each in the first minutes of trading on the New York Stock Exchange.
That is a 73% jump from the initial asking price of $26 a share, and it means the company is now valued at a little over $31bn (£19bn).
Samira Hussain reports from New York.