An ETF is a basket of stocks that reflects the composition of an Index, like the Sensex or the Nifty. ETF prices reflect the net asset value of basket of stocks in which it is investing. In many ways, it is similar to mutual funds. Exchange Traded Funds (ETFs) are actually Index Funds that are listed and traded on exchanges like stocks and are passively managed. Mutual funds aim to generate alpha by outperforming a market benchmark, whereas ETFs aim to track the relevant index and replicate it returns. To invest in ETFs you need to have demat and trading account with a stock broker.