S&P Dow Jones Indices announced on September 4 that Bloom Energy, Illumina and Everpure will enter the S&P 500 before the market opens on Monday, September 21, 2026, displacing Molson Coors, The Trade Desk and Builders FirstSource. The quarterly rebalance will also sweep four technology companies into the S&P 100, replacing Honeywell Aerospace, Nike, Simon Property Group and Colgate-Palmolive in a shift that underscores the growing dominance of artificial intelligence infrastructure in U.S. equity benchmarks.
What Changes on Sept. 21
The S&P 500 additions reshape three sectors. Bloom Energy (NYSE: BE), a fuel-cell power systems maker classified under Industrials, will replace Molson Coors Beverage (NYSE: TAP), a Consumer Staples name. Illumina (NASDAQ: ILMN), the gene-sequencing company in Health Care, will take the seat vacated by Builders FirstSource (NYSE: BLDR), an Industrials construction firm. Everpure (NYSE: P), a data-storage provider in Information Technology, will replace The Trade Desk (NASDAQ: TTD), a digital advertising platform in Communication Services.
The announcement at 5:15 p.m. EDT on September 4 triggered immediate after-hours trading. Bloom Energy surged 7.35 percent to close at $252.87 during the regular session before extending gains in extended-hours trading, according to Yahoo Finance data. Everpure added 2.2 percent after the bell to $101.68, lifting its implied market capitalization by roughly $723 million, StockTi reported. Illumina climbed 2.1 percent to $222.88, adding approximately $704 million in after-hours value, even though the stock closed the regular session down 1.6 percent, per StockTi analysis.
The mechanical reason for these reactions is straightforward. Index-tracking funds that replicate the S&P 500 must purchase shares of the incoming companies and sell those of the departing ones before the effective date. The buying pressure is predictable in direction but not in magnitude, since S&P does not disclose final index weights ahead of time.
S&P 100 Tilts Further Toward AI Infrastructure
The concurrent S&P 100 rebalance reinforces the same theme. Dell Technologies (NYSE: DELL), Palo Alto Networks (NASDAQ: PANW), Arista Networks (NASDAQ: ANET) and SanDisk (NASDAQ: SNDK) will enter the index of the 100 largest U.S. companies, replacing Honeywell Aerospace (NYSE: HONA), Nike (NYSE: NKE), Simon Property Group (NYSE: SPG) and Colgate-Palmolive (NYSE: CL).
All four incoming names are classified in Information Technology. Dell makes servers and storage used in data centers. Arista supplies the network switches that connect AI computing clusters. Palo Alto Networks provides cybersecurity platforms. SanDisk, spun out of Western Digital in February 2025, manufactures flash memory used in high-performance storage systems. Together, they represent four layers of the capital-spending wave behind generative AI.
Nike's removal from the S&P 100 is particularly notable. The sneaker maker's market capitalization has fallen to roughly $57 billion from a peak near $280 billion, according to ainvest.com analysis. While Nike remains in the broader S&P 500, its exclusion from the top-100 tier reflects sustained revenue stagnation and declining cash flow at a time when the market is rewarding technology-driven growth.
Broader MidCap and SmallCap Shifts
The rebalance extends across the S&P MidCap 400 and SmallCap 600. HubSpot (NYSE: HUBS), AGNC Investment (NASDAQ: AGNC), Corcept Therapeutics (NASDAQ: CORT) and Brinker International (NYSE: EAT) will join the MidCap 400, replacing Everpure, Illumina, Boston Beer (NYSE: SAM) and Capri Holdings (NYSE: CPRI). In the SmallCap 600, Molson Coors, The Trade Desk and Builders FirstSource — the companies exiting the S&P 500 — will be demoted, alongside other shifts.
S&P Dow Jones Indices stated that the changes "ensure that each index is more representative of its market capitalization range" and noted that the companies being removed from the SmallCap 600 "are no longer representative of the small-cap market space."
What It Means for Investors
Quarterly rebalances are routine, but this one carries a signal beyond the mechanical. The S&P 500 is shedding a consumer staples brewer, a digital advertising platform and a construction company, replacing them with a clean-energy hardware maker, a gene-sequencing specialist and a data-storage firm. The S&P 100 is simultaneously pushing out a consumer goods giant, a real estate investment trust and a legacy industrial conglomerate in favor of four information technology companies.
For investors in index-tracking products, the changes create forced buying in BE, ILMN and P — and forced selling in TAP, TTD and BLDR. The same dynamic applies at the S&P 100 level with DELL, PANW, ANET and SNDK entering and HONA, NKE, SPG and CL exiting. The rebalance takes effect before trading opens on September 21.
The headline index is not the only thing shifting. The sector composition of the S&P 500 continues to tilt toward technology and health care, away from consumer staples, industrials and real estate. Whether this represents a structural rebasing or a cyclical extreme is a question the next few quarters will answer.
Sources
- S&P Dow Jones Indices, press release, September 4, 2026: https://press.spglobal.com/2026-09-04-Bloom-Energy,-Illumina,-and-Everpure-Set-to-Join-S-P-500-Others-to-Join-S-P-100,-S-P-MidCap-400,-and-S-P-SmallCap-600
- Investor's Business Daily, "Bloom Energy, Illumina, Everpure Rise On S&P 500 Inclusion," September 4, 2026: https://www.investors.com/news/bloom-energy-illumina-everpure-rise-sp-500-index-inclusion/
- StockTi, "Everpure Surges 2.2% After S&P 500 Inclusion, Adding $723M," September 4, 2026: https://stockti.com/everpure-surges-2-2-after-s-p-500-inclusion-adding-723m
- StockTi, "Illumina's S&P 500 Comeback Sparks $704M After-Hours Surge," September 4, 2026: https://stockti.com/illumina-s-s-p-500-comeback-sparks-704m-after-hours-surge
