The largest shareholder of UK betting operator William Hill has publicly opposed the company merging with Canadian online gambling operator Amaya Gaming, the parent company of PokerStars.

Last Friday, word broke that Hills and Amaya were considering a “merger of equals” that would create an omni-channel gambling behemoth. On Thursday, London-based Parvus Asset Management, which owns 14.3% of Hills, said it was “extremely concerned” by the merger talk.

In an open letter to Hills’ board of directors, Parvus said the proposed tie-up was based on “limited strategic logic.” Parvus co-founders Mads Eg Gensmann and Edoardo Mercadante told the board to “stop wasting valuable time and shareholder resources pursuing this value-destroying deal,” while urging the board to pursue “all alternative options available, including a sale” of the UK bookmaker.

Gensmann later told Reuters that it “shouldn’t take more than five minutes of the board’s time to realize this deal doesn’t pass the smell test.” Parvus’ principal objections center around Amaya deriving the vast majority of its revenues from online poker, which Parvus called the financially least-attractive segment of online gambling.