S&P 500 adds Marvell and Flex, flags 4 more potential entrants

The S&P 500 added two companies Friday and signaled four more could join the benchmark index, which tracks more than $20 trillion in assets.

"The index was designed to reward companies that have already earned their place through profitability and staying power," said Jay Woods, chief strategist at Freedom Capital Markets.

Marvell Technology Inc. and Flex Ltd. replaced Pool Corp. and Campbell's Co. in the reconstitution effective June 5. Marvell shares have surged 230% in 2026, driven by AI chip demand. The index operator also flagged Bloom Energy Corp., Astera Labs Inc., Alnylam Pharmaceuticals Inc., and Reddit Inc. as potential near-term additions, according to a Barron's report.

The additions come as S&P Dow Jones Indices declined to relax eligibility rules for megacap IPOs, keeping SpaceX — which targets a $1.75 trillion valuation in its June 12 debut — out of the index until at least June 2027. JPMorgan estimated SpaceX would draw about $10 billion in passive inflows upon inclusion.

The four flagged candidates reflect the index's push to capture large-cap growth across technology, energy, and biotech. Bloom Energy, a fuel-cell manufacturer, has benefited from rising data-center power demand. Astera Labs, a semiconductor connectivity company, has ridden the AI infrastructure buildout. Alnylam Pharmaceuticals has gained on RNAi therapeutic approvals, while Reddit has drawn attention as a social-media platform with advertising momentum.

To join the S&P 500, a company must trade publicly for at least 12 months, report GAAP profitability in the most recent quarter and trailing four quarters, and maintain a free float of at least 10%. SpaceX meets none of those criteria. The company posted a net loss of $4.94 billion in 2025 on revenue of $18.67 billion, and its free float is estimated at 3% to 4%.

The divergence in index-provider approaches has widened. Nasdaq and FTSE Russell have shortened trading-history requirements to fast-track large IPOs into their benchmarks. Nasdaq's new rules, announced in March, allow rapid inclusion of newly listed companies into the Nasdaq 100. FTSE Russell has made similar adjustments.

Still, the S&P 500's dominance as the U.S. equity benchmark appears secure. More than $20 trillion in assets track the index, compared with $1.4 trillion for the Nasdaq 100. "The omission of SpaceX in the S&P 500 is just not a strong enough incentive to drive institutions to change their benchmarks," said Peter Andersen, founder of Andersen Capital Management.

The U.S. 10-year Treasury yield rose 4 basis points to 4.38% on Monday, while the S&P 500 fell 0.6% to 5,412. The Cboe Volatility Index climbed 1.2 points to 16.8, reflecting modest hedging demand as investors weighed the index changes against a broader tech selloff.

This article is for informational purposes only and does not constitute investment advice.