If an employee works for a company where he has been granted RSUs, when RSUs are vested, he will have RSU income in his Pay stubs/W-2. At the same time, there will be ordinary income taxes paid for RSU in the Tax Withholding section of W-2 details. Usually there are multiple vestings so it will be stacks one on top of each other to get to the total. A lot of times, companies provide a report called Summary of Ordinary Income related to Employee Stock, which is a very helpful document.

Say 100 shares vested and the market price at vesting was $10. So the RSU income will be $1,000. At vesting, say 40 shares were sold to pay tax, he would have been left with 60 shares. The amount of tax paid on the vesting would be $400. The cost basis now for the remaining 60 shares would be $10/share so total cost basis $600. When he sold later at $20/shares, he will have Capital Gain of $600 (Gross Sales Proceeds $1,200 - Cost Basis $600).

If he sold the remaining 60 shares on the same day of vesting, the cost basis is still $10/share cos he paid ord income tax up to the $10/share price.

RSU is given without a pre-determined price - it is going to use the market price at vesting.

If you found shares with a grant price, that would be Stock Options (NQSO or ISO). Don't confuse between the types of employee stocks.

Good luck. I know the answer is late.