Marvell Technology and Flex Set to Join S&P 500; Others to Join S&P MidCap 400 and S&P SmallCap 600

S&P Dow Jones Indices announced index reconstitutions effective before the open on June 22, 2026, as part of its quarterly rebalance. Marvell Technology and Flex will be added to the S&P 500 while Pool Corp and Campbell’s will be removed. Numerous swaps across the S&P MidCap 400 and S&P SmallCap 600 (eg, Roku, Semtech, Sanmina, Blackbaud moving between mid and small caps) will also take effect. These committee-driven changes can prompt predictable flows as passive S&P 500-linked funds buy additions and sell deletions, creating short-term demand/supply pressure on the named stocks around the effective date.