Andreessen Horowitz, often referred to as "a16z," is a prominent venture capital firm based in Menlo Park, California. It was founded in 2009 by Marc Andreessen and Ben Horowitz, both of whom are well-known figures in the tech industry. Andreessen Horowitz is one of the leading venture capital firms in Silicon Valley and has gained a reputation for its investments in technology companies, particularly in the areas of software, internet, and more recently, blockchain and cryptocurrency.