Marvell Technology (NASDAQ: MRVL) will join the S&P 500 before the open on Monday, June 22, 2026, along with electronics-manufacturing-services giant Flex Ltd. (NASDAQ: FLEX). The two companies replace Pool Corp. (NASDAQ: POOL) and The Campbell’s Company (NASDAQ: CPB) in the benchmark’s quarterly rebalance, announced by S&P Dow Jones Indices on June 5, 2026.
The reshuffle is the most concentrated AI-and-electronics swap in years. Marvell has nearly tripled in 2026 on accelerating data-center revenue, a deepened partnership with Nvidia, and the debut of its new Teralynx T100 switch silicon. Flex has more than doubled as data-center customers scramble for its rack-level integration capacity. On the other side of the trade, Pool Corp. and Campbell’s drop out after months of weak end-market demand and shrinking relative market caps.
The Rebalance in One Picture
| Ticker | Company | Action | Price (Jun 11) | Market Cap | YTD Return |
|---|---|---|---|---|---|
| MRVL | Marvell Technology | Added | $280.71 | $246B | +230% |
| FLEX | Flex Ltd. | Added | $152.00 | ~$58B | +121% |
| POOL | Pool Corp. | Removed | $192.34 | ~$7.0B | -20% |
| CPB | The Campbell’s Company | Removed | $22.73 | ~$6.8B | -8% |
The combined market cap of the two additions (~$304B) is roughly twenty times the combined market cap of the two deletions (~$14B). That gap is why index methodologists felt compelled to make the swap now rather than wait — Pool and Campbell’s had drifted well below S&P 500’s minimum-size and float thresholds, while Marvell and Flex had cleared them for several months running.
Why Marvell Cleared the Bar
Marvell’s data-center business now dwarfs every other segment. In its Q1 FY2027 results reported on May 27, 2026, Marvell posted record revenue of $2.42 billion, gross margin of 58.9%, and operating cash flow of $638.8 million. Guidance for the current quarter was raised to $2.7 billion, implying double-digit sequential growth driven by what management called “exceptional AI-related bookings.”
Three product and partnership catalysts compounded that earnings momentum into the S&P decision window:
- NVLink Fusion partnership with Nvidia. Announced March 31, 2026, this slots Marvell’s custom-silicon and interconnect IP into Nvidia’s rack-scale AI platforms. Nvidia also took an equity stake.
- Teralynx T100 switch. On June 1, 2026, Marvell launched the industry’s first 102.4 Tbps switch silicon, built on 3nm, purpose-designed for AI back-end fabrics. The stock jumped sharply that week.
- Polariton acquisition. The April 22, 2026 deal for Polariton Technologies extends optical performance scaling to 3.2T, deepening Marvell’s grip on the long-haul AI-cluster opportunity.
The cumulative effect: Marvell entered June 2026 with a $246 billion market cap, a 52-week range of $61.44 to $324.20, and a trailing P/E of roughly 96x — comfortably past every S&P 500 eligibility threshold (positive GAAP earnings over four quarters, U.S. domicile, market cap, float, and liquidity).
What Index Inclusion Mechanically Means
The S&P 500 is the most widely tracked equity index in the world. The largest single tracker, the SPDR S&P 500 ETF (SPY), alone holds roughly $784 billion in assets. iShares’ IVV and Vanguard’s VOO each hold hundreds of billions more, and that is before counting non-ETF index mutual funds and institutional separate accounts benchmarked to the index.
When a stock is added to the S&P 500, every passive vehicle benchmarked to it must own a market-cap-weighted slice of the new constituent by the close on the effective date. For Marvell, at a ~$246B market cap, that means a non-trivial weighting in the S&P 500 (somewhere between 0.4% and 0.5% based on free-float-adjusted shares). Index-fund rebalancing is mechanical and price-insensitive, which is why “index-inclusion days” tend to produce closing-cross volume spikes far larger than a typical session.
Marvell’s 2026 Run, in One Chart
Why Pool Corp. and Campbell’s Are Out
Both deletions tell the same story from different sectors. Pool Corp., the dominant U.S. distributor of pool and outdoor-living products, has been hit by a slowdown in new-pool construction and a softer renovation cycle since rates re-rose; the stock is down roughly 20% YTD and the market cap has slipped to around $7 billion. Campbell’s, after rebranding from Campbell Soup, has struggled with a 4% sales decline and snack-division margin pressure in its most recent quarter; UBS recently cut its price target to $17, and the market cap is now about $6.8 billion.
The S&P 500’s methodology does not formally rank constituents by market cap, but the Index Committee’s practice is to remove names whose float-adjusted market caps drift well below the floor it requires for new additions (currently $20.5 billion). At $6 to $7 billion, both Pool and Campbell’s sat far below that bar. Both are moving to the S&P MidCap 400, the destination index for S&P 500 deletions of this size.
The “Inclusion Pop” Risk
Stocks added to the S&P 500 have historically rallied between announcement and effective date as index-tracking funds (and front-runners) bid them up. The well-documented pattern, sometimes called the “index effect,” has weakened in recent years as more passive money has begun rebalancing only at the close on effective day rather than spreading the trade in advance. Academic work on the post-2010 period — including research by Bennett, Stulz and Wang — finds the inclusion premium has shrunk meaningfully versus the 1990s and 2000s.
For Marvell specifically, much of the run-up appears to already be in the stock. Shares are up 230% YTD, trade at 96x trailing earnings, and have already absorbed the Nvidia partnership, the Teralynx launch, and the index-inclusion news. The classic “buy the rumor, sell the news” warning typically applies most strongly when a name has rallied this hard into its inclusion date.
What to Watch Next
- June 20 (Friday) close: The last cash session before inclusion. Closing-cross volume in MRVL and FLEX will be the largest signal of how much passive money is rebalancing into the names.
- June 22 open: The new weights go live in tracker portfolios. Any early-session deviation from the prior close is information about how much demand was already pulled forward.
- Sector weights: Information Technology’s weight in the S&P 500 ticks up modestly with two semis-adjacent names entering and a discretionary/staples pair exiting.
- Marvell Q2 FY2027 earnings: Scheduled for late August 2026. The first quarterly print as an index member is when shareholder-base composition starts to shift materially toward passive holders.
Sources
- S&P Dow Jones Indices — June 5, 2026 rebalance announcement
- Marvell Technology Q1 FY2027 earnings release (May 27, 2026)
- Marvell — NVLink Fusion partnership with Nvidia (March 31, 2026)
- Marvell — Teralynx T100 announcement (June 1, 2026)
- State Street — SPDR S&P 500 ETF (SPY) factsheet
- S&P U.S. Indices Methodology (eligibility criteria)
- Bennett, Stulz, Wang — “The Disappearance of the S&P 500 Effect”
Disclosure: This article was produced with AI assistance and reviewed before publication. It is for informational purposes only and is not investment advice.