Cost Basis of RSUs when some are sold to cover taxes

[neemeyer]

300 shares
sold 89 to pay taxes
sale proceeds Box 1d  shows amount for 211 shares
Cost of basis is empty? Should it be 0? amount of 300 shares? or amount of 211 shares?
3 year vest

[teeboli]

Cost basis is the price of the share after deposit into your account.  You need to pay tax on the difference between the Basis and the sale date price per share.  Box 1d looks like your stock appreciated in price since basis and reflects total proceeds.  Cost basis = 89 x price of each share when it vested and dropped into your account.