The exchange operator of CBOE Global Markets wrote a letter to the US Securities and Exchange Commission (SEC), recommending they not interfere in the development of a Bitcoin exchange-traded-fund (ETF) because they are similar to other commodity-based ETFs, March 23.
ETFs are a type of exchange-traded-product (ETP). An ETF is a marketable security that tracks an index, a commodity, bonds, or a basket of assets like an index fund. ETFs trade like common stock on a stock exchange and typically have higher daily liquidity and lower fees than shares of mutual funds.
https://cointelegraph.com/news/cboe-recommends-that-the-sec-allows-bitcoin-exchange-traded-funds