Chime Financial, listed as CHYM, will enter the index in the Financials sector. NorthWestern Energy Group, ticker NWE, is classified in Utilities and will be removed on the same effective date.

Black Hills, an existing S&P MidCap 400 constituent, is acquiring NorthWestern in a deal expected to close on November 13. After the merger, the combined company will remain in the index and take the name Bright Horizon Energy Corp., with the ticker HZN.