Twitter raised over US$57 million from venture capitalist growth funding, although exact numbers are not publicly disclosed. Twitter's first A round of funding was for an undisclosed amount that is rumored to have been between US$1 million and US$5 million.[157] Its second B round of funding in 2008 was for US$22 million[158] and its third C round of funding in 2009 was for US$35 million from Institutional Venture Partners and Benchmark Capital along with an undisclosed amount from other investors including Union Square Ventures, Spark Capital, and Insight Venture Partners.[157] Twitter is backed by Union Square Ventures, Digital Garage, Spark Capital, and Bezos Expeditions.[159]
In May 2008, The Industry Standard remarked that Twitter's long-term viability is limited by a lack of revenue.[160] Twitter board member Todd Chaffee forecast that the company could profit from e-commerce, noting that users may want to buy items directly from Twitter since it already provides product recommendations and promotions.[161]
By March 2009 communications consultant Bill Douglass predicted in an interview that Twitter would be worth $1 billion within six months,[162] which came to pass when the company closed a financing round valuing it at $1 billion in September of that year.[163]
The company raised US$200 million in new venture capital in December 2010, at a valuation of approximately US$3.7 billion.[164] In March 2011, 35,000 Twitter shares sold for US$34.50 each on Sharespost, an implied valuation of US$7.8 billion.[165] In August 2010 Twitter announced a "significant" investment lead by Digital Sky Technologies that, at US$800 million, was reported to be the largest venture round in history.[166]
In December 2011, the Saudi prince Alwaleed bin Talal invested $300 million in Twitter. The company was valued at $8.4 billion at the time.[167]