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S&P 500 Shake-Up: Marvell and Flex In, Pool and Campbell's Out — Effective June 22

S&P Dow Jones Indices is swapping out Pool Corp and Campbell's for Marvell Technology and Flex ahead of the quarterly rebalance. Marvell jumped ~5% after-hours on the news; Flex gained ~4%.

OurAlpha

09 Jun 2026 — 2 min read

Passive index funds must buy newly added constituents at their index weight — the built-in buying pressure behind Marvell's and Flex's after-hours pop.

TL;DR

S&P Dow Jones Indices announced that Marvell Technology (MRVL) and Flex (FLEX) will join the S&P 500, replacing Pool Corp (POOL) and Campbell's (CPB), with the changes taking effect before the open on June 22.

Added: Marvell Technology (MRVL), Flex (FLEX)
Removed: Pool Corp (POOL), Campbell's (CPB)^[CNBC]
Effective: Monday, June 22, before the open — coinciding with the quarterly rebalance
Reaction: Marvell surged ~5% after-hours on the announcement; Flex gained ~4%^{[Yahoo Finance]}

S&P Dow Jones Indices announced its quarterly index rebalance, adding Marvell Technology (MRVL) and Flex (FLEX) to the S&P 500 while removing Pool Corp (POOL) and Campbell's (CPB). The changes take effect before the open on Monday, June 22.

The Additions and Deletions

Per CNBC, the S&P 500 constituent changes are as follows^[^CNBC^]:

Added: Marvell Technology (MRVL) — a semiconductor company supplying chips and components for AI infrastructure
Added: Flex (FLEX) — a contract manufacturer serving tech giants including Apple (AAPL) and Nvidia (NVDA)
Removed: Pool Corp (POOL), Campbell's (CPB)

Notably, Campbell's had just reported earnings on June 8 with a slight EPS beat and in-line revenue — but that doesn't factor into an index removal. Constituent changes are driven by market cap, liquidity, and other eligibility criteria, not quarterly results.

Why Index Inclusion Moves Stocks

Per Yahoo Finance, Marvell gained ~5% and Flex ~4% after-hours following the announcement^[^{Yahoo Finance}^]. By the June 8 premarket session, TheStreet reported Marvell up ~9% and Flex up ~4.3% — with Marvell getting an additional lift from a broader semiconductor rally^[^TheStreet^].

The mechanism is straightforward: the massive universe of passive funds and ETFs that track the S&P 500 must purchase newly added names at their index weight, creating a predictable wave of buying. The reverse applies to deletions.

The AI Angle Some Media Are Running

Fortune and others have framed the swap — AI-adjacent Marvell and Flex displacing Pool and Campbell's — as another sign of AI-related companies gaining ground within major indexes^[^Fortune^]. Worth keeping in mind: index rebalances follow rules-based eligibility criteria and carry no implicit judgment on any stock's future prospects.

What Comes Next

The changes officially take effect before the June 22 open. Earlier this week, markets also had to digest the May CPI print and Oracle (ORCL) earnings on June 10, followed by Adobe (ADBE) results on June 11.