NEW YORK (MarketWatch) -- Bitcoin prices rose above $600 on Friday for the first time since March 19 on a closing basis, according to CoinDesk's bitcoin price index. In recent action, bitcoin was at $608.27, up 7.5% from Thursday. Bitcoin prices had been stuck in the $400s in May until pushing above $500 last week. Prices took a tumble in late March as concerns spread about a further crackdown against bitcoin in China. CoinDesk's index tracks prices on three exchanges.