** Kodiak Gas Services' KGS.N shares up 8.2% premarket to $33.38, a four-week high, as co set to join S&P SmallCap 600 index .SPCY

** Compression service provider for oil and gas industry to replace NV5 Global NVEE.O in SPCY effective Weds, Aug 6, S&P Dow Jones Indices said late Fri

** Industrial testing, inspection, and engineering services firm Acuren TIC.N acquiring NVEE in deal expected to close soon, per S&P Dow Jones

** Stephens analyst Melissa Roberts says passive funds will need to purchase 5.3 mln KGS shares, which implies 5 days of buying demand

** The Woodlands, Texas-based KGS has ~87.86 mln shares outstanding for $2.8 bln market cap

** Swedish private equity firm EQT AB EQTAB.ST is largest KGS holder with ~31.27 mln shares, ~36% stake, per LSEG data

** YTD, KGS shares down 23% through Fri close

** 11 of 12 analysts rate KGS "strong buy" or "buy", 1 rates "hold" and median PT is $45, according to LSEG

(Lance Tupper is a Reuters market analyst. The views expressed are his own)

((lance.tupper@tr.com 1-646-279-6380))