Shares of Astera Labs (NASDAQ:ALAB) and Rocket Lab (NASDAQ:RKLB) advanced in extended trading on Thursday after Nasdaq announced the companies would be added to the Nasdaq-100 Index as part of its June quarterly rebalance.
Astera Labs, which supplies semiconductor connectivity components used in artificial intelligence data centers, rose about 5% in after-hours trading to $383.50. Rocket Lab, a developer of space technology, climbed nearly 11% to $126.95 in the same session.
Nasdaq said five companies will join the Nasdaq-100 before the market opens on June 22: Astera Labs, Rocket Lab, CoreWeave (NASDAQ:CRWV), Nebius Group (NASDAQ:NBIS) and Teradyne (NASDAQ:TER).
Those new additions will replace five existing constituents in the index: Charter Communications (NASDAQ:CHTR), Cognizant Technology Solutions (NASDAQ:CTSH), Insmed (NASDAQ:INSM), Verisk Analytics (NASDAQ:VRSK) and Zscaler (NASDAQ:ZS).
Inclusion in the Nasdaq-100 - the benchmark that tracks the largest non-financial companies listed on the Nasdaq exchange - often spurs buying pressure on stocks that are newly admitted, as exchange-traded products and passive funds rebalance portfolios to mirror the index.
The announcement represents a further milestone for both Astera Labs and Rocket Lab. Their shares have posted strong gains over the past year amid investor interest in artificial intelligence infrastructure and the commercial space sector, respectively.
Context and market mechanics
The quarterly reshuffling of the Nasdaq-100 is a routine index maintenance process intended to ensure the benchmark reflects the current largest eligible non-financial companies on the Nasdaq exchange. When a company is added, funds that track the index typically purchase shares to match their holdings to the new composition, which can increase near-term demand for the newly included names.
For corporate issuers, index inclusion can alter investor composition and trading dynamics. For passive investors and index funds, the rebalance necessitates reweighting holdings to align with the updated index constituents.
Market reaction summary
- Astera Labs rose about 5% after hours to $383.50.
- Rocket Lab increased nearly 11% after hours to $126.95.
- CoreWeave, Nebius Group and Teradyne were also named as additions effective June 22.
- Charter Communications, Cognizant, Insmed, Verisk Analytics and Zscaler were designated as the companies leaving the Nasdaq-100.
Implications
The move is likely to affect demand patterns for the newly added stocks as index tracking and ETF strategies adjust positions. Sectors directly referenced by the additions include semiconductor infrastructure, space technology and industrial automation, reflecting investor interest in AI infrastructure and commercial space activity.