Bloom Energy and Illumina Join S&P 500 in September Rebalance

S&P Dow Jones Indices announced its quarterly rebalance updates, adding Bloom Energy, Illumina, and Everpure to the benchmark S&P 500 index while making structural adjustments across mega-cap, mid-cap, and small-cap indices effective September 21, 2026. The reconstitution impacts passive funds tracking these major indexes, as institutional managers must automatically reallocate holdings to match the updated index weights before the market opens on the effective date.

Following the announcement, Bloom Energy Corp. (BE) shares traded at $252.87, climbing 7.35% from a previous close of $235.55, according to Finnhub market data.

Under the official index adjustments, Bloom Energy, Everpure, and Illumina will officially enter the S&P 500 prior to the opening bell on Monday, September 21, 2026. These incoming companies will replace Molson Coors Beverage Co., The Trade Desk Inc., and Builders FirstSource Inc., which are being removed from the large-cap index.

S&P 100 Shifts

Alongside the S&P 500 changes, S&P Dow Jones Indices restructured the S&P 100 index. Dell Technologies, Palo Alto Networks, Arista Networks, and Sandisk are joining the premier mega-cap tier. To accommodate these additions, Honeywell Aerospace, Nike, Simon Property Group, and Colgate-Palmolive are being removed from the S&P 100.

Understanding Index Rebalances

Quarterly rebalances serve to maintain the accurate representation of market sectors as company capitalizations fluctuate over time. Inclusion in the S&P 500 often triggers increased trading volume and short-term price appreciation due to mandatory buying by exchange-traded funds and index mutual funds that mirror the benchmark. Conversely, removal forces institutional funds to liquidate positions, impacting the departing equities.