A gold ETF is an exchange-traded fund and a substitute for physical gold. Every investor knows that investing in physical gold can be cumbersome and insecure. This is where gold ETFs help you stay invested in gold, without actually having to own any physical gold. In a gold ETF, which is a commodity exchange-traded fund, the only underlying asset is gold. One gold ETF unit is equivalent to one gram of gold. Gold ETFs are traded on the National Stock Exchange (NSE) and the Bombay Stock Exchange (BSE).