as a generality because your specific info isn't known but when you get RSU's income is added to your w-2 for X units you got at some value. Y units are sold to cover the taxes. thus, you have tax basis in the units sold which would be Y times income added to your w-2 for x units divided by X.
what is the broker showing as tax basis. is it as above.
withholding for the exercise would be on your w-2. whether it was sufficient to cover the actual income taxes is a different question. Talk to your payroll or human resource department to get any info you are missing.
