** Stifel trims stock rating on casino operator MGM Resorts MGM.N to "hold" from "buy"

** Media mogul Barry Diller's People Inc earlier this month, proposed to buy MGM at $48.30 a share in cash - valuing it at more than $18 billion

** Stifel views Diller's offer for MGM as meaningfully less attractive

** Says shares had a nice move higher leading up to deal announcement and higher quality of MGM’s assets warrant a greater relative valuation premium

** "We think it is likely that Diller will have to come in with a higher offer in order to get a deal done," says Stifel

** Adds bid structure allows for private equity involvement without taking over control of enterprise, mitigating probability of a competing bid from PE

** "We struggle to identify a rational strategic bidder for a company this large and diversified," says Stifel

** Median PT of 26 brokerages covering MGM is $46 - data compiled by LSEG

** Shares of MGM up ~0.5% to $49

** Including session gains, stock up 35% YTD