Jan 11 (Reuters) - Cryptocurrency asset manager Grayscale Investments plans to file for a covered call exchange-traded fund in an effort to allow investors to generate income from options on its Grayscale Bitcoin Trust, said CEO Michael Sonnenshein.

GBTC began trading as an ETF Thursday on NYSE Arca after the U.S. Securities and Exchange Commission approved its conversion -- along with a spate of other proposals for spot bitcoin ETFs -- a day earlier. (Reporting by Hannah Lang in Washington)