Philip Morris (NYSE: PM) shares are down over 10% since rumors first surfaced that it was in talks with sister company Altria Group (NYSE: MO) about a re-merger. While the companies are trying to relay a message that the merger would be a great strategic move, behind the scenes several large shareholders are lobbying against the deal, sources said. The belief is that if Philip Morris abandoned the deal it could save a lot of future heartache and shares would snapback sharply.

Although neither company is talking publicly or privately about terminating the deal at this point, executives at Philip Morris are said to be “perplexed” by the reaction in the stock since the deal announcement. Calls with analysts and investors have done little so far to soothe fears.

“We see little strategic or financial merit in a potential PM-MO recombination,” Morgan Stanley analyst Pamela Kaufman exclaimed in a note to clients on Thursday. The analyst sees a limited scope for synergies, low EPS accretion, and a deal resulting in a lower valuation. Citi analyst Adam Spielman called the current arguments for the deal “unconvincing” and said a deal would “[s]ubtract value in e-vapor due to MO’s non-compete agreement with Juul.” He sees a decent chance the deal gets rejected.

The companies still have time to convince shareholders and the analyst community about the benefits of the deal, but with each passing day more bricks pill up on the side against the deal. And because a shareholder vote is needed, rumors have already started that a large activist investor with some sway could throw his or her hat in the ring and come out against the deal.

Overall, while the companies had hoped for a slam-dunk merger deal that was greeted with high-fives and pats on the back, instead they received a swarm of unpleasant phones calls and a plethora of Wall Street critics. Time will tell if they can avoid the deal going down in flames.