Coinbase's President & Chief Operating Officer Asiff Hirji late Tuesday said the popular digital-currency platform would kick off a crypto-focused index fund. Hirji told CNBC during an interview on its "Fast Money" segment that the planned index fund is intended to give retail investors broad exposure to virtual currencies. The COO said the fund is still in the works and would be targeted to accredited investors, with a specified net worth. Hirji said the index fund would be market-cap weighted but didn't offer more details.