Twitter, appropriately enough, announced its IPO plan via a tweet. But, under a recent change in US law, companies with annual sales under $1 billion can file their IPO prospectus confidentially with the SEC (Securities and Exchange Commission), which Twitter has done. It means potential investors in the micro-blogging phenomena may only have a short time to pore over the firm’s books before a listing goes ahead

The change in US law is not without criticism. Some argue that it reduces scrutiny on companies.

Moreover, giving companies freedom to choose when to disclose they have filed to go public makes it impossible to tell how close a share sale may be.

“[Twitter] may have filed confidentially two months ago,” said Anthony McCusker, a partner at law firm Goodwin Procter, quoted by the Financial Times (FT), which might mean an IPO is on the cards as early as next month.

Documents filed with the SEC, adds the FT report, are designed to provide investors with a detailed blueprint of businesses before an IPO. However, they only need to be made public three weeks before companies embark on the investor roadshows that immediately precede share sales.

Max Wolff of Greencrest Capital, speaking to Reuters, nonetheless estimated Twitter should break even this year and is on track for 40 per cent annual growth (at a $1 billion annual revenue run rate), raking in money through targeted advertising.

“It’s completely conquered mobile,” said Wolff, “[and] has an enormous social network. It’s becoming a key utility as a second screen to TV and it’s literally the first draft of history.”

Twitter has been valued by private investors at more than $10 billion.

The IPO move follows news earlier this week that Twitter has spent a reported $350 million buying mobile ad platform MoPub.