This scenario occurs repeatedly in the business world, where the company buys a nonrefundable, theoretically non-transferable ticket for an employee who leaves the company before the ticket is used. Most airlines, including United, have a provision that allows the company to do a "name change" for an additional fee. Given that your former company is a Fortune 500, I would bet that they have a similar agreement with their local UA sales rep.

So in fact much of the value of your ticket could likely be reused for travel by another employee.