Twitter has unsealed the documents for its planned initial public offering (IPO) of stock and says it hopes to raise up to $1bn (€738m).

Speculation is mounting that social networking giant Twitter may launch on the stock market as early as this August.

Billionaire money manager George Soros reported a nearly 2% stake in Manchester United Plc in one of the first revelations of investors in the British soccer club’s controversial initial public offering earlier this month.

Facebook is already trading like a public company as insiders and wealthy investors use private marketplaces to buy and sell stock in the social networking company, ahead of its initial offering.