S&P Dow Jones Indices announced a new round of changes as part of the March 2026 index rebalance, updating the composition of several major benchmarks, including the S&P 500, S&P 100, S&P MidCap 400, and S&P SmallCap 600.
These adjustments help ensure each index accurately represents its target market capitalization range and sector composition. The changes will take effect before the market opens on March 23, 2026, prompting index funds and ETFs that track these benchmarks to rebalance their holdings.
Because trillions of dollars track these indices, additions and removals often trigger significant trading activity as funds buy newly added stocks and sell those leaving the index.
S&P 100 Changes
The S&P 100, which tracks the largest and most established companies in the S&P 500, also saw several changes.
Added to the S&P 100
| Company | Ticker | Sector |
|---|---|---|
| Micron Technology | MU | Information Technology |
| Lam Research | LRCX | Information Technology |
| Applied Materials | AMAT | Information Technology |
| GE Vernova | GEV | Industrials |
Removed from the S&P 100
| Company | Ticker | Sector |
|---|---|---|
| PayPal Holdings | PYPL | Financials |
| American International Group | AIG | Financials |
| MetLife | MET | Financials |
| Target | TGT | Consumer Staples |
These additions highlight the continued dominance of semiconductor and AI infrastructure companies within large-cap U.S. equity markets.
S&P 500 Changes
The most notable update in this rebalance is the addition of several companies tied to AI infrastructure, optical networking, and communications technology.
Companies Added to the S&P 500
| Company | Ticker | Sector |
|---|---|---|
| Vertiv Holdings | VRT | Industrials |
| Lumentum Holdings | LITE | Information Technology |
| Coherent | COHR | Information Technology |
| EchoStar | SATS | Communication Services |
Companies Removed from the S&P 500
| Company | Ticker | Sector |
|---|---|---|
| Match Group | MTCH | Communication Services |
| Molina Healthcare | MOH | Health Care |
| Lamb Weston Holdings | LW | Consumer Staples |
| Paycom Software | PAYC | Industrials |
Vertiv, Lumentum, and Coherent have all benefited from growing demand for AI infrastructure and data center connectivity, while EchoStar operates in satellite communications. These additions reflect the increasing influence of technology and communications infrastructure companies in the U.S. equity market.
S&P MidCap 400 Changes
Several companies are moving into the S&P MidCap 400, which represents medium-sized U.S. companies.
Added to the S&P MidCap 400
| Company | Ticker | Sector |
|---|---|---|
| Solstice Advanced Materials | SOLS | Materials |
| SiTime | SITM | Information Technology |
| Moog | MOG.A | Industrials |
| InterDigital | IDCC | Information Technology |
| Vicor | VICR | Industrials |
| CareTrust REIT | CTRE | Real Estate |
Removed from the S&P MidCap 400
| Company | Ticker | Sector |
|---|---|---|
| Lumentum Holdings | LITE | Information Technology |
| Coherent | COHR | Information Technology |
| EchoStar | SATS | Communication Services |
| ZoomInfo Technologies | GTM | Communication Services |
| ASGN | ASGN | Information Technology |
| Kemper | KMPR | Financials |
The removal of Lumentum, Coherent, and EchoStar reflects their promotion to the S&P 500.
S&P SmallCap 600 Changes
The small-cap index also saw multiple adjustments.
Added to the S&P SmallCap 600
| Company | Ticker | Sector |
|---|---|---|
| Match Group | MTCH | Communication Services |
| Molina Healthcare | MOH | Health Care |
| Lamb Weston Holdings | LW | Consumer Staples |
| Paycom Software | PAYC | Industrials |
| VSE | VSEC | Industrials |
| Argan | AGX | Industrials |
| Rithm Capital | RITM | Financials |
Additional SmallCap Adjustment (March 13)
| Action | Company | Ticker | Sector |
|---|---|---|---|
| Addition | NAPCO Security Technologies | NSSC | Information Technology |
| Removal | Alexander & Baldwin | ALEX | Real Estate |
These changes help ensure companies remain in the index that best reflects their market capitalization and size category.
When the Rebalance Takes Effect
The index changes will take effect before the market opens on March 23, 2026.
Institutional investors and ETFs that track S&P indices typically adjust their portfolios at the close of trading in the prior session, which can lead to increased trading volume and short-term price movements in affected stocks.
Why Index Rebalances Matter
Index rebalances are closely watched because they can influence stock prices in the short term. When a company is added to a major index like the S&P 500:
- Passive funds tracking the index must buy shares.
- Liquidity and visibility often increase.
- Trading volume typically spikes around the rebalance date.
Conversely, companies removed from the index may experience selling pressure as funds adjust their holdings. With trillions of dollars benchmarked against S&P indices, even small changes can have noticeable effects on the stocks involved.
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