Victor Mateo is a Trader at Axe Capital where he was regarded as a capable employee and problem solver who is top profit contributor to the firm. But was considered a hothead that reacts poorly to public humiliation.
He was fired after doing poorly in the SEC compliance drill that Axe organized with the reasons that he performed trades without Axe's approval, which will put the company and reputation in jeopardy. Wendy Rhoades regarded Axe's spur of the moment decision to lay Victor off as an issue because he will seek all ways to exact revenge.
He later was funded outside and forced back into Axe Capital in Season 4.