iShares Russell 2000 Small-Cap Index Fund (MDSKX) is an open-end mutual fund managed by BlackRock that seeks to replicate the investment results of the Russell 2000 Index by investing primarily in a portfolio of small-cap U.S. equities selected to correspond to the index's composition; it provides exposure to approximately 2,000 small-capitalization companies across diverse sectors including financial services, industrials, healthcare, technology, and consumer cyclical stocks, with top holdings such as Sprouts Farmers Market Inc., iShares Russell 2000 ETF, Insmed Inc., FTAI Aviation Ltd., and BlackRock Cash Funds Treasury SL Agency representing about 2.81% of the portfolio. The fund offers Investor A shares with a net expense ratio of 0.37%, a minimum initial investment of $1,000, and daily pricing, targeting U.S. investors seeking small-blend market exposure. Launched on April 9, 1997, and domiciled in the United States, it operates with total net assets of approximately $2.76 billion and share class size of $218.73 million, available for sale exclusively in the United States. Managed by a team including Jennifer Hsui (since 2016) and newer co-managers Peter Sietsema, Matt Waldron, and Steven White (since April 2025), the fund maintains a blend investment style focused on small-cap stocks. In portfolio characteristics, it emphasizes U.S. stocks (98.54% allocation), with minor non-U.S. stock exposure (1.55%) and negligible cash positions. Recent management team expansions in April 2025 added co-managers Sietsema, Waldron, and White to enhance operational oversight amid BlackRock's broader strategic focus on index funds.