The MyIndex series, including My500™, My400™ and My600™, enables market participants to incorporate specific index preferences while remaining grounded in our flagship U.S. equity benchmarks, such as the S&P 500®, S&P MidCap 400® and S&P SmallCap 600®.

MyIndex offers comprehensive index market coverage with no gaps or overlaps. This structure provides a consistent foundation across large-, mid- and small-cap indices while supporting a range of customization needs.

A Closer Look at the Indices Behind MyIndex™

  • My500™

    The index at the heart of My500, the S&P 500 (also known as “The 500®” and “US 500™”), is regarded as the best single gauge of the large-cap U.S. equity market. It is the world’s most-tracked index by AUM, with USD 23 trillion indexed or benchmarked to the index.* The 500 covers leading large-cap companies and represents a broad cross-section of the U.S. equity market, covering approximately 80% of the U.S. equity market’s available market cap.

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  • My400™

    As a benchmark for the U.S. mid-cap equity market, the S&P MidCap 400—which underlies My400—is designed to reflect this market segment’s distinctive characteristics. Many mid-cap stocks, by definition, have survived beyond their startup phases and may offer both stability and potential growth opportunities.

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  • My600™

    Tracking the U.S. small-cap market, which is typically known for less liquidity and potentially less financial viability than large caps, the S&P SmallCap 600—which underlies My600—tracks 600 small-sized companies that meet specific inclusion criteria to ensure they meet certain liquid and financial thresholds.

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*as of December 31, 2025.

S&P 500®, S&P MidCap 400®, S&P SmallCap 600®, The 500®, US 500™, S&P 400®, S&P 600®, MyIndex™, My500™, My400™ and My600™ are trademarks of S&P Global, Inc. (“S&P Global”) or its affiliates