The Fidelity Extended Market Index Fund (FSMAX) primarily dedicates a minimum of 80% of its assets to common equities that comprise the Dow Jones U.S. Completion Total Stock Market Index. This benchmark is designed to track the performance of American companies with mid- to small-market capitalizations. To effectively mirror the index's returns, the fund's management utilizes a sophisticated statistical sampling approach. This methodology assesses various critical metrics including market capitalization, sector representation, dividend income, price-to-earnings (P/E) ratios, price-to-book (P/B) ratios, and earnings growth, allowing the fund to achieve its objective with a more selective portfolio of securities.