Was the Isaac Dulgarian vs Yadier del Valle UFC fight fixed after sportsbooks issued mass refunds?

On Saturday, November 1, 2025, at the UFC Apex in Las Vegas, Nevada, Cuban featherweight fighter Yadier del Valle upset American Isaac Dulgarian by submitting him in the first round.

The result stunned many, but what grabbed even more attention was the strange betting activity that happened just before the fight began. Several major U.S. sportsbooks reacted by offering refunds after lines and prop bets moved in a highly unusual fashion.Shortly before the fight, Dulgarian opened as a strong favourite at around –240. Yet as the clock wound down, his odds tightened to about –160, while the prop bet that the fight would end in the first round dropped from +850 to +475.

Such dramatic swings signalled heavy late bets, prompting books like DraftKings to pull the line entirely. Further, both Caesars Sportsbook and William Hill issued refunds to losing bettors.

No official investigation has yet been confirmed, though speculation is running high.

What really happened before and after the Isaac Dulgarian vs Yadier del Valle UFC fight?

The clash between Isaac Dulgarian and Yadier del Valle on Nov 1, 2025, rapidly turned from fight night to betting-alert night. Dulgarian was expected to dominate, yet del Valle secured a submission via rear-naked choke in just 3 minutes and 41 seconds of round one.

The bout’s timing and finish alone were surprising, but the heavy and sudden betting action in del Valle’s favour set off alarm bells. Reports show Dulgarian’s odds tightening, while the first-round finish prop moved massively.

Some sportsbooks swiftly reacted: Caesars and William Hill publicly stated they would issue credits to mobile customers who lost single bets or parlay legs. DraftKings removed the prop line altogether, citing awareness of the situation. While neither the Nevada State Athletic Commission nor the Ultimate Fighting Championship (UFC) has announced a formal probe, the unusual financial flows, combined with the shock result cast a long shadow.

Why the Isaac Dulgarian vs Yadier del Valle UFC fight is drawing more scrutiny after Vegas 110?

For Isaac Dulgarian, the loss has deep repercussions. Analysts and fans alike questioned how a favoured fighter looked so off on a big stage. On the broadcast, former UFC fighter-analyst Michael Chiesa called Dulgarian’s performance “an F- performance… absolute trash”.The upset win took Yadier del Valle’s record to 10-0 and placed him in a far stronger spotlight, yet the spotlight is now also on the integrity of the matchup. Also Read: Andrew Tate becomes new Misfits Boxing CEO after old KSI tweet leads to explosive company takeoverThe late betting swings recall past incidents in MMA that triggered formal investigations, and many observers believe this fight may draw serious regulatory interest. Until then, bettors, regulators and fans are left watching how sportsbooks handle the fallout and whether the UFC will clarify what took place behind the scenes.