Index investing is a strategy that involves purchasing a portfolio of assets designed to replicate the performance of a specific market index, such as the S&P 500 or Dow Jones Industrial Average. This approach allows investors to gain broad market exposure while minimizing costs and management fees. By investing in index funds or exchange-traded funds (ETFs), individuals can achieve diversification and reduce the risks associated with picking individual stocks. Index investing is favored for its simplicity and effectiveness, making it a popular choice for both novice and experienced investors alike.