** Shares of payments processor Shift4 Payments FOUR.N rise 6.2% to $103.05 after the bell

** FOUR will join the S&P MidCap 400 effective prior to opening of trading on Nov. 20, S&P Dow Jones Indices says

** Co will replace healthtech firm R1 RCM, which is set to be taken private by PE firms TowerBrook Capital Partners and Clayton, Dubilier & Rice (CD&R) in an $8.9 bln deal

** S&P MidCap 400 offers investors with a benchmark for mid-sized companies

** FOUR has a market capitalization of $8.74 bln - LSEG

** As of last close, FOUR shares up 30.1% YTD

(Reporting by Arasu Kannagi Basil in Bengaluru)

((ArasuKannagi.Basil@thomsonreuters.com;))