S&P reconstitutes MidCap 400 and SmallCap 600 with ALSN, GT changes

Key Facts

1Allison Transmission Holdings, ticker ALSN, will enter the S&P MidCap 400, replacing Goodyear Tire & Rubber, ticker GT.

2Goodyear Tire & Rubber, ticker GT, will join the S&P SmallCap 600, replacing Stellar Bancorp, ticker STEL, after Prosperity Bancshares acquired Stellar Bancorp.

3The changes will become effective before the open of trading on Monday, July 6, 2026.

In a scheduled index reshuffle that reflects changes in U.S. benchmark membership, Allison Transmission Holdings, ticker ALSN, will enter the S&P MidCap 400, replacing Goodyear Tire & Rubber, ticker GT. Goodyear Tire & Rubber will in turn join the S&P SmallCap 600, replacing Stellar Bancorp, ticker STEL, after Prosperity Bancshares acquired Stellar Bancorp. The changes take effect before the open on Monday, July 6, 2026.

Index additions can attract passive demand as funds tracking the benchmark adjust holdings, but the impact is often muted when the reconstitution has been widely anticipated. Per market data, ALSN closed at $112.74 on June 30, 2026, with an intraday range of $110.79 to $117.13, while GT closed at $6.60 and traded between $6.50 and $6.65 in the same session.

What to watch is trading behavior around the July 6 effective date, when index-related flows may become more visible in the days just ahead of the move. Based on the latest prices, ALSN is still trading near the middle of its recent range, while GT is priced at a much lower nominal level, which could make any benchmark-driven demand more apparent in percentage terms.