The venture capital firm is also adding a new general partner to its ranks. : Andreessen Horowitz on Monday debuted a $300 million investment fund that will specialize in cryptoassets and projects that build on blockchains, the distributed ledger technology that underpins virtual currencies like Bitcoin and Ethereum. The prominent Silicon Valley venture capital firm on Monday also added another general partner to its ranks who will co-lead the new fund: Kathryn Haun, a former federal prosecutor best known for her work against corrupt agents tied to the Silk Road drug market.