(Updates with stock movement in the last paragraph.)
Reddit (RDDT) will replace AvalonBay Communities (AVB) in the S&P 500 prior to the opening of trading on Aug. 18, S&P Dow Jones Indices said Thursday.
Equity Residential (EQR), a S&P 500 constituent, is acquiring AvalonBay in a deal expected to be completed soon, S&P said, adding that the combined company will be renamed Vivmark Residential (VMRK) and will remain in the index post merger.
Reddit's shares were up over 12% after-market hours.
Price: $177.80, Change: $+19.68, Percent Change: +12.45%