Twitter reports $645m loss for 2013 in first results
6 February 2014 Last updated at 11:50 GMT
Microblogging site Twitter has reported a net loss of $645m (£396m) for 2013, just three months after its flotation on the New York Stock Exchange.
Shares in the company plunged in trading after the company announced its first financial results as a public company.
Michelle Fleury reports from New York.