While watching Andrei Arlovski knock out Travis Browne, I thought to myself, “How many times have I seen a heavyweight underdog win?”

It seemed to me that when considering weight class that there have been a lot of heavyweight underdogs who have won their fights compared to their lighter weight counterparts.

In order to prove my initial thought, I tracked the last 51 fights in each weight class to see if putting money on heavyweight underdogs was a good idea.

Using 5Dimes betting odds, I put a theoretical $100 on each UFC fight until the weight class reached 51 fights. The chart below shows the amount of money earned, or lost, after betting $5100 on each division. (Note: Women’s Bantamweight (42 fights) and Women’s Strawweight (21 fights) did not reach 51 fights.)

The bantamweight division and the middleweight division ended up as the two most profitable weight classes to bet on, both passing $1000 dollars in profit.

One of the biggest pushes for the division was the +710 underdog win by TJ Dillashaw over former UFC Bantamweight Champion Renan Barao.

Although this win was seen as one of the biggest underdog wins in the UFC’s history, the title of biggest underdog win for the bantamweight division went Johnny Eduardo over Eddie Wineland at a +735 underdog. Frankie Saenz was also a +725 underdog in his win over Iuri Alcantara.

The heavyweight division did end up in the positive range of $201, which is a very small profit for betting $5100.

The lightweight and welterweight division were, by far, the worst two divisions to bet on. Not only did betting on both divisions lose over $600, but both divisions continued the downward trend with more fights.

After betting on 70 welterweight fights ($7000), the bettor would have lost $1325 if they had bet on all underdogs. After betting on 90 lightweight fights ($9000), the bettor would have lost $970 if they had bet on all underdogs.

The data proves that betting on the divisions with the most fighters (welterweight, lightweight and featherweight) are the riskiest to bet on. Other than that, it seems like judging an underdogs success by division is random at best.