Brokerage firm Bernstein has sharply raised its price target on Coinbase shares from $310 to $510, and reiterated its outperform rating on the stock. Bernstein said that the Coinbase exchange is the only cryptocurrency-native company in the Standard & Poor's 500 index, and despite competitive pressures, Coinbase continues to dominate U.S. market trading, while also solidifying its role as a universal bank for cryptocurrencies.