Grayscale Investments is exploring options to return a portion of capital underlying its flagship Grayscale Bitcoin (GBTC) product if the SEC refuses to grant a bitcoin exchange-traded fund (ETF), according to a report.Read MoreCoinDeskGrayscale Investments is exploring options to return a portion of capital underlying its flagship Grayscale Bitcoin (GBTC) product if the SEC refuses to grant a bitcoin exchange-traded fund (ETF), according to a report.