** Cava Group's CAVA.N shares up 2.7% to $89 in premarket trading as Mediterranean restaurant chain set to join S&P MidCap 400 index .IDX next week

** CAVA to replace Altair Engineering in the IDX effective Mon, Mar 31, the S&P Dow Jones Indices said late Weds

** Germany's Siemens SIEGn.DE bought Altair in $10.6 bln deal

** With ~115.59 mln shares outstanding, CAVA has ~$10 bln market cap, per LSEG data

** Through Weds, stock down 23% YTD. Shares closed at $69.17 a year ago

** Of 17 analysts covering CAVA, recommendation breakdown is 10 "strong buy" or "buy", rest "hold"; median PT of $120 implies ~38% upside to last close

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

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