S&P 500 Changes Start Trading Monday Sept 22: APP, HOOD, EME In; MKTX, CZR, ENPH Out

S&P 500 Index Rebalancing Report

Effective Date: September 22, 2025
Source: S&P Dow Jones Indices official announcement

Additions to the S&P 500

  1. AppLovin (APP)

    • Mobile app technology company focused on gaming, AI-driven app discovery, and monetization platforms.

    • Added in place of MarketAxess Holdings (MKTX).

  2. Robinhood Markets (HOOD)

    • Online brokerage platform known for commission-free trading and retail investor engagement.

    • Added in place of Caesars Entertainment (CZR).

  3. Emcor Group (EME)

    • Construction and facilities services provider, specializing in mechanical and electrical construction, industrial services, and energy efficiency.

    • Added in place of Enphase Energy (ENPH).

Removals from the S&P 500

(These firms will move to the S&P SmallCap 600)

  • MarketAxess Holdings (MKTX) – electronic bond trading platform.

  • Caesars Entertainment (CZR) – casino and hospitality operator.

  • Enphase Energy (ENPH) – solar energy technology firm.

 Market Implications

  • ETF and Index Fund Flows:
    Index-tracking funds (SPY, IVV, VOO, etc.) will sell shares of MKTX, CZR, ENPH and buy APP, HOOD, and EME. This usually leads to short-term stock price volatility around rebalancing.

  • Sector Impact:

    • Tech weighting increases with AppLovin and Robinhood.

    • Industrial exposure strengthened with Emcor.

    • Energy and consumer discretionary exposure trimmed with the removal of Enphase and Caesars.

  • Investor Takeaway:
    Such changes highlight growing importance of app-based platforms and diversified industrial services in the U.S. economy, while volatility in energy tech and gaming sectors drives exits.