Twitter files for IPO worth up to $15bn

Social media giant Twitter has filed preparatory documents to the US regulatory for an initial public offering (IPO).

The group revealed its intentions in a tweet, which read: "We've confidentially submitted an S1 to the SEC for a planned IPO. This Tweet does not constitute an offer of any securities for sale." The San Francisco-based firm, which has more than 200m active monthly users, has managed to keep information about its IPO out of the public domain until now. The seven year old company may come to market before the end of 2013, and could be valued as high as $15bn at its IPO, according to some estimates. Earlier this year, Twitter was valued at $10bn in private transactions, which included...