CoStar Group to Exit Nasdaq-100, Replaced by Lumentum After Stock Slump

CoStar Group Inc. (CSGP) will be removed from the Nasdaq-100 Index® effective before the market opens on Monday, May 18, 2026. Nasdaq announced the change on May 8, 2026.

Lumentum Holdings Inc. will replace CoStar Group in the index. The Nasdaq-100 tracks the 100 largest non-financial companies listed on the Nasdaq stock market.

CoStar’s market capitalization fell significantly as its stock recently hit a 52-week low. Lumentum’s valuation surged during the same period. This shift in market value prompted the change in the market-cap-weighted index.