Shares of Reddit rose Thursday evening on news that the social media company will join the S&P 500 index. Sun Communities will be added to the S&P MidCap 400. Reddit will be added to the S&P 500 index before the open on Tuesday, August 18. It will replace AvalonBay Communities (AVB), which is being acquired by S&P 500 member Equity Residential (EQR).… Copyright ©2026 Investor’s Business Daily, LLC. All rights reserved. 87990cbe856818d5eddac44c7b1cdeb8