According to a Delaware filing by Uber Technologies, it has sold stock in the fast-growing privately held transportation service to private equity giant TPG. In addition, according to sources who have seen other stock documents, Uber has also taken a major investment from Google Ventures. The overall valuation for the San Francisco company, according to the document — filed on August 1 — and also sources, is $3.5 billion. AllThingsD had reported in late July that Uber was raising at such a valuation and that both TPG and Google Ventures were the principal new investors. At the time, Uber management declined to comment on rumors and even tried to tamp them down. The public filing indicates that TPG has bought 775,092 shares of Series C-2 preferred shares at $114.03. That is an investment of just under $90 million.