Reddit Set to Join S&P 500 and Sun Communities to Join S&P MidCap 400

NEW YORK, Aug. 13, 2026 /PRNewswire/ -- S&P Dow Jones Indices will make the following changes to the S&P 500 and S&P MidCap 400: 

• Reddit Inc. (NYSE: RDDT) will replace AvalonBay Communities Inc. (NYSE: AVB) in the S&P 500 effective prior to the opening of trading on Tuesday, August 18. S&P 500 constituent Equity Residential (NYSE: EQR) is acquiring AvalonBay Communities in a deal expected to be completed soon, pending final conditions. Post merger, the combined company will be renamed Vivmark Residential (NYSE: VMRK) and will remain in the S&P 500.
• Sun Communities Inc. (NYSE: SUI) will replace Webster Financial Corp. (NYSE: WBS) in the S&P MidCap 400 effective prior to the opening of trading on Thursday, August 20. Banco Santander S.A. (BMEX / NYSE: SAN) is acquiring Webster Financial in a deal expected to be completed soon pending final conditions.

Following is a summary of the changes that will take place prior to the open of trading on the effective date:

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SOURCE S&P Dow Jones Indices