An Exchange-Traded Fund (ETF) is an investment fund that holds a collection of assets such as stocks, bonds, or commodities and is traded on a stock exchange like a regular stock. ETFs allow investors to buy many assets in a single product, making diversification easier and often more affordable.

ETFs are popular because they usually have lower fees, are easy to trade, and provide flexibility for both short-term and long-term investors. For example, a stock market ETF may track the performance of an index such as the S&P 500, allowing investors to invest in many companies at once.