Twitter has reported a net loss of $645 million for last year.
The popular micro-blogging site, which reported a loss of $8.7 million a year earlier, made its market debut on the New York stock exchange in November.
In its annual earnings report, published tonight, it showed its total revenue for last year was $665 million, more than double the £316 million of 2012.
By the fourth quarter of 2013, the number of monthly Twitter users around the world had increased to 241 million, the newly released figures show, although growth is slowing down.
Chief executive Dick Costolo said the site would only get better.
"Twitter finished a great year with our strongest financial quarter to date," he said.
"We are the only platform that is public, real-time, conversational and widely distributed and I'm excited by the number of initiatives we have under way to further build upon the Twitter experience."
Twitter's public debut on the stock exchange was the most highly anticipated since that of Facebook in May 2012.
The San Francisco-based company was launched seven years ago. Last year the company named the UK as its biggest market outside America.