why is KR down, and where to find SP 500 change?

After close today, there’s to be a few companies added to the S&P 500 index, KDP being one of them.
Any links that tell which are being booted off the index?

Just wondering if Kroger (KR) might be one of them.

KR reported very good numbers yesterday. Short term call option premiums looked very good, I was all set to buy shares and write covered calls this morning. But even though the market is not having a sell-off today, KR dropped more than 7%. So, I’m holding off…just puzzled as to why the drop in share price. And just wondering if by any chance the above is a possibility. Did a quick google search, didn’t find any info.

Never mind, found it…IDGP and UnderArmour (UAA) are getting the boot out of the index.