Shares in Twitter opened at $US45.10 each in the first minutes of trading on the New York Stock Exchange on Thursday.
The BBC reports that was 73% above the initial asking price of $US26 per share and it means the company is now valued at a little over $US31 billion.
More than 13 million shares were traded once they became available an hour after the stock exchange opened.
It is the biggest technology listing since Facebook in 2012. Twitter has more than 230 million users, but is yet to make a profit.
It lost $US69 million in the first six months of 2013, on revenues of $US254 million. About 85% of revenues come from advertising on its site.
The BBC reports shares in newly-listed companies are often volatile on their first day of trading and
Twitter's stock price was below its opening price by midday.