The U.S. Securities and Exchange Commission (SEC) has extended its review of SkyBridge Capital's application for a bitcoin exchange-traded fund, a filing by the U.S. regulatory agency shows.

Anthony Scarammuci's SkyBridge Capital submitted an application on May 6 to list and trade shares of the First Trust SkyBridge Bitcoin ETF Trust. The SEC has extended its initial 45-day review period to Aug. 25.The agency has received public comment on the application.U.S. regulators have been extremely reticent to approve such investment vehicles, which would provide retail investors with access to the bitcoin market without having to own bitcoin itself. ETFs are a staple of many retirement portfolios.