S&P Dow Jones Indices announced on June 5 that Marvell Technology and Flex Ltd. will be added to the S&P 500 index, effective prior to market open on June 22, 2026. Marvell shares climbed roughly 6% in after-hours trading on the news.
The additions are part of the S&P 500’s quarterly rebalance. Marvell (MRVL) will replace Pool Corp. (POOL), while Flex (FLEX) takes the spot vacated by The Campbell’s Company (CPB).
Every index fund and ETF benchmarked to the S&P 500 is now obligated to buy shares of both companies, creating a wave of forced demand that often pushes prices higher independent of fundamentals.
Why these two, and why now
Marvell Technology is a semiconductor firm that has carved out a significant niche in AI infrastructure. The company designs custom chips and networking components that power the data centers at the heart of the current AI buildout.
