Lumentum Holdings to Join S&P 500 on March 23, Exiting MidCap 400
Lumentum Holdings will be added to the S&P 500 effective before trading opens March 23 as part of the quarterly rebalance. On the same date, it will be removed from the S&P MidCap 400 to align the indices with market-cap ranges.
1. Rebalance Overview
The index provider will implement its quarterly rebalance prior to the open on March 23, 2026, adjusting constituents across multiple benchmarks. Changes will span the S&P 100, S&P 500, S&P MidCap 400 and S&P SmallCap 600 to better reflect market-cap ranges.
2. Lumentum's Index Changes
Lumentum Holdings will enter the S&P 500 on March 23, marking its debut in the benchmark index. Simultaneously, it will be removed from the S&P MidCap 400 as part of the realignment process.
3. Market Implications
Inclusion in the S&P 500 is expected to drive passive fund inflows and boost trading volume in Lumentum's shares. Removal from the MidCap 400 may marginally adjust investor composition but is offset by the prominence gained in the broader index.