Russia\'s DST Global II, the investment firm controlled by Russian billionaire and Mail.ru web portal founder Yury Millner, will lead a pool of investors to buy a 5 per cent stake in the Twitter microblogging service, Kommersant business daily reported on Monday.DST Global is expected to pay $400 million for the stake in a deal that would value Twitter at $8 billion, the paper said.The New York Times reported on Thursday that the San Francisco-based Twitter was in the process of a financing round that would be split into two and would be led by DST Global. Previous investors, including the venture capital firm Kleiner Perkins Caufield & Byers, will also participate, the paper said.DST Global II representative Leonid Solovyov declined to comment.Twitter, which was founded in 2006, made over $200 million in revenue from online advertising last year and is close to profitability. At these levels, the company\'s valuation is roughly 40 times sales, according to an estimate of Hudson Square Research.Millner and his business partner Alisher Usmanov have been interested in acquiring a stake in Twitter for two years now. Twitter, which was worth about $1 billion in 2009, has seen its value already soar to $3.7 billion in 2010. The company earlier held negotiations on attracting investor capital with DST Global but made its choice in favor of Kleiner Perkins Caufield & Byers, Spark Capital, Benchmark Capital and Union Square Ventures to raise $200 million.Early in July, sources close to Twitter valued it at no less than $7 billion, saying that the company was planning to attract several hundred million U.S. dollars.