Carta, a platform that allows users to buy, sell, and trade privately held assets, announced Monday it closed $300 million in Series E funding that valued the company at $1.7 billion. Andreessen Horowitz led the round and Marc Andreessen will join the company's board. Lightspeed Venture Partners, Goldman Sachs Principal Strategic Investments, Tiger Global and Thrive Capital joined the round as their first investment in the company. Carta most recently raised $80 million in December at $800 million valuation.