S&P Rebalancing: Pinterest Joins S&P 400 While Under Armour Moves to Small-Cap Index
Written by Emily J. Thompson, Senior Investment Analyst
Updated: Dec 08 2025
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Should l Buy ?
Source: SeekingAlpha
Index Changes Announcement: S&P Dow Jones Indices announced multiple index changes effective December 22, including Pinterest joining the S&P MidCap 400 index.
Promotions and Removals: Comfort Systems USA will be promoted to the S&P 500, while several companies, including Under Armour and Power Integrations, will move to the S&P SmallCap 600.
Stock Performance: Following the announcement, shares of Pinterest rose nearly 4% in premarket trading on Monday.
Additional Deletions: Several companies, including SPX Technologies and Dycom Industries, are set to be removed from the S&P SmallCap 600 index.
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About the author
Emily J. Thompson
Emily J. Thompson, a Chartered Financial Analyst (CFA) with 12 years in investment research, graduated with honors from the Wharton School. Specializing in industrial and technology stocks, she provides in-depth analysis for Intellectia’s earnings and market brief reports.
