** Fitness products maker Peloton Interactive PTON.O shares up 3.5% before the bell to $5.36 as it's poised to join the S&P SmallCap 600 index .SPCY next week

** PTON to replace Enviri Corp NVRI.N in SPCY effective Weds, May 27, S&P Dow Jones Indices announced late Thurs

** Enviri expects to close sale of Clean Earth to France's Veolia Environnement VIE.PA and complete spin-off of Harsco Environmental and Rail into a standalone publicly traded co on June 1

** S&P Dow Jones said the new publicly traded co is "not expected to be representative of the small-cap market space"

** Stephens analyst Melissa Roberts said she expects passive funds will need to purchase 55 mln PTON shares, implying 4 days of buying demand

** PTON has ~433 mln shares outstanding for $2.2 bln market cap

** Earlier this month, PTON posted fiscal Q3 rev above Wall Street's expectations

** Avg rating of 21 analysts is "hold"; median PT $7.75, per LSEG data

** Through Thurs close, stock down 16% YTD