 NEW YORK, April 6, 2021 PRNewswire -- Envista Holdings Corp. NYSE: NVST will replace InterDigital Inc. NASD: IDCC in the SP MidCap 400, and InterDigital will replace SEACOR Holdings Inc. NYSE: CKH in the SP SmallCap 600 effective prior to the opening of trading on Monday, April 12. American Industrial Partners is acquiring SEACOR Holdings in a deal expected to be completed soon pending final closing conditions. 