A typical structure for RSUs (Uber included) is to delay activation until liquidity is possible. Until then, a contractual obligation to deliver the RSUs is wh

A typical structure for RSUs (Uber included) is to delay activation until liquidity is possible. Until then, a contractual obligation to deliver the RSUs is what the employee actually possesses (after vest). Employees are free to exercise RSUs and pay the income tax hit, but I can't imagine a scenario when that would be rational. Especially since the company holds vested RSUs for separated employees. Nobody at Uber is having to sell their Tesla P80 to cover the tax from their newly-vested RSUs after their annual cliff occurs.