Andreessen Horowitz, which has investments in Facebook, Twitter and Zynga, has raised $1.5bn for its third fund in one of the largest US venture capital fund fundraisings of last year.

The venture capital firm, set up by Netscape co-founder Marc Andreessen and former Opsware Inc. chief executive Ben Horowitz, has now raised $2.7bn since it was launched in June 2009.