Marvell Technology is joining the S&P 500, and the message is bigger than one index change. AI infrastructure is no longer a side trade, it is becoming part of the market’s core ownership base.
Marvell Technology and Flex are being added to the S&P 500 before the open on June 22, replacing Pool Corporation and Campbell's Company in a quarterly rebalance that says a lot about where the market thinks durable growth now lives.
The immediate story is mechanical. Index funds that track the S&P 500 will need to own Marvell and Flex, which creates forced buying around the effective date. But the more important story is structural. A chip designer tied closely to custom AI silicon and data center infrastructure is being moved into the most watched equity benchmark in the world, at the same time a pool equipment distributor and a packaged food company are moving out.
That is not just a reshuffle. It is a signal.
According to Reuters, S&P Dow Jones Indices announced the changes on Friday, June 5, after Marvell cleared the profitability hurdle needed for entry. Investing.com reported that Marvell shares rose about 6% in after-hours trading after the news, while Flex gained roughly 4%. Pool slipped in late trading and Campbell's was little changed, which is about what you would expect when the buying pressure sits clearly on the incoming names.
For much of the AI boom, the market conversation has been dominated by Nvidia. That makes sense. Nvidia still sits at the center of the GPU market and has become the shorthand for AI infrastructure spending. But the next phase is broader. Hyperscalers do not want one supplier, one architecture or one cost curve. They want chips tuned to their own workloads, their own data centers and their own economics.
That is where Marvell has become more important. The company helps cloud customers design custom chips and provides the networking and optical technology that moves data through AI data centers. In late May, Marvell forecast that its custom chip business would top $10 billion in revenue in fiscal 2029. It also raised its fiscal 2028 revenue outlook to about $16.5 billion, from a previous forecast of $15 billion.
Those are not small revisions. They show that demand is moving from broad excitement about AI into concrete infrastructure orders. Marvell said first-quarter revenue rose 28% to $2.42 billion, ahead of analyst expectations, while data center revenue reached $1.83 billion. The company also projected second-quarter revenue of $2.70 billion, plus or minus 5%, again above Wall Street estimates.
CEO Matt Murphy told analysts that Marvell has custom engagements across all major U.S. hyperscalers. That matters because it places the company in the same strategic conversation as Broadcom, which has built a large business around custom AI silicon for cloud clients. Investors are not just paying for a chip cycle here. They are paying for a role inside the capital spending plans of Alphabet, Amazon, Microsoft and other large AI infrastructure buyers.
Index inclusion changes the ownership base
Joining the S&P 500 does not change Marvell's technology, customers or margins overnight. It changes who has to own the stock. Passive funds, ETFs and benchmarked managers now have a clear reason to buy shares whether or not they have a fresh view on valuation.
That can make the short-term trading messy. Marvell had already been volatile before the announcement, rising sharply after Nvidia CEO Jensen Huang publicly praised the company, then falling with the broader semiconductor group after Broadcom's earnings failed to lift sentiment. The index news gives the stock a new technical support point, but it does not remove the basic question investors still have to answer: how much future AI infrastructure growth is already reflected in the price?
That is the real valuation conversation now. Marvell is not being judged like a traditional semiconductor supplier. It is being measured against the size of the AI data center buildout, the pace at which hyperscalers move toward custom silicon and the margins available in that work. If custom chips keep taking a larger share of AI infrastructure budgets, Marvell's place in the S&P 500 will look less like a reward for past performance and more like recognition of a new market category.
Flex adds another layer to the same story. The company is not a chip designer, but it sits in the manufacturing and supply chain side of advanced electronics. Its inclusion reinforces the idea that AI infrastructure is not only about processors. It is also about boards, systems, power, logistics and the physical buildout needed to make cloud computing capacity real.
The exits are just as telling. Pool Corporation and Campbell's Company are not broken businesses because they are leaving the S&P 500. But their removal shows how the benchmark keeps adapting to the economy it is supposed to represent. Consumer staples and housing-linked names still matter, but the center of gravity has shifted toward companies tied to data centers, cloud infrastructure and specialized compute.
For investors, the next thing to watch is not simply whether Marvell pops into the June 22 rebalance. It is whether the company's custom silicon targets continue to move higher as hyperscalers spend through 2026 and into 2027. Index inclusion can bring buyers. Sustained revenue growth has to keep them there.
Also read: Amazon's AI spending is becoming a harder sell inside the company • Chip stocks learned that the AI trade still answers to rates • Google is renting SpaceX compute because AI capacity now beats control
