 NEW YORK, April 5, 2021 PRNewswire -- Cara Therapeutics Inc. NASD:CARA will replace MTS Systems Corp. NASD:MTSC in the SP SmallCap 600 effective prior to the opening of trading on Thursday, April 8. SP 500 constituent Amphenol Corp. NYSE: APH is acquiring MTS Systems in a deal expected to be completed soon pending final closing conditions. 