Jose Aldo wasn't about to sign a Reebok deal straight out, and is still negotiating with two other companies along with the UFC's main sponsor.
Since the UFC signed the Reebok sponsorship with the UFC, most fighters have fallen in line. One who most definitely has not is featherweight champion Jose Aldo. Aldo has routinely criticized the deal, and turned down a personal sponsorship deal with Reebok when it was offered to him due to his lucrative deal with Venum. Now that his Venum deal is almost up though, he's negotiating with a few suitors, including both of the above.