What happened
S&P Dow Jones Indices is adding HubSpot, AGNC, Corcept, and Brinker to the S&P MidCap 400 index.
The same announcement places Bloom Energy, Illumina, and Everpure into the S&P 500, and PaloAlto, Arista Networks, and Sandisk Networks into the S&P 100, with all changes effective September 21, 2026.
Why it matters
Index additions often prompt fund managers who track these benchmarks to adjust their portfolios, potentially affecting trading volumes and stock prices.
The selection of companies across small-, mid-, and large-cap indices reflects shifting market positions and may signal which firms are gaining or losing weight in the eyes of index methodology.
Key facts
HubSpot, AGNC, Corcept, and Brinker join the S&P MidCap 400.
Bloom Energy, Illumina, and Everpure join the S&P 500.
PaloAlto, Arista Networks, and Sandisk Networks join the S&P 100.
All index changes take effect on September 21, 2026.
What to watch next
Investors may track these stocks around the September 21, 2026 effective date for potential index-fund rebalancing activity.
Further announcements from S&P Dow Jones Indices could clarify whether additional index changes are planned for the same period.