Bank Nifty, officially Nifty Bank, is an index made up of the largest and most liquid banking stocks listed on NSE, such as HDFC Bank, ICICI Bank, SBI and Axis Bank. It tracks how the banking sector as a whole is doing. You cannot buy an index directly, but you can trade Bank Nifty futures and options, and its options are among the most traded contracts in India. Because banks are sensitive to interest rates, RBI policy and credit news, Bank Nifty tends to move more sharply than Nifty 50 in a day. That attracts intraday traders and also causes fast losses. The lot size and expiry schedule for Bank Nifty derivatives have changed several times, so check NSE's current contract specifications before trading it. Many beginners meet Bank Nifty through options first, which is the riskiest place to start.