A benchmark is a standard index or reference point used to evaluate the performance of an investment portfolio, mutual fund, or individual security — providing a comparable market baseline against which returns, risk, and portfolio construction are assessed. For Indian equity mutual funds, SEBI mandates the disclosure of a relevant benchmark index in the Scheme Information Document — large-cap funds are benchmarked against the Nifty 50 or BSE Sensex, mid-cap funds against the Nifty Midcap 150 or BSE Midcap, and small-cap funds against the Nifty Smallcap 250 or BSE Smallcap. Since 2018, SEBI mandates benchmarking against the Total Return Index (TRI) variant — which includes dividend reinvestment — rather than the price return index, ensuring investors accurately assess whether a fund has genuinely outperformed what the market delivered in total return terms. For individual stock analysis, the stock's return is compared to the relevant sectoral index (e.g., Nifty Bank for banking stocks, Nifty IT for technology companies) to determine whether it has generated alpha beyond the sector's movement. For portfolio managers and institutional investors in India, benchmark selection is a critical strategic decision — choosing an inappropriate benchmark can make average performance appear exceptional, or strong performance appear mediocre, distorting investor decision-making and fee justification.