Sell-to-cover — definition & guide

An automatic RSU or option mechanism where the company's stock plan administrator sells just enough vested shares to pay the employer's statutory tax withholding, delivering the remaining shares to the employee.

Sell-to-cover is the default tax mechanism on RSUs at many public companies. At vest, the administrator sells enough shares, at whatever the market price is that morning, to cover the federal supplemental withholding (22% or 37%), state withholding, Social Security, and Medicare. The employee receives the remaining net shares in the brokerage account.

Example: 2,000 RSUs vest at $180, producing $360,000 of wage income. Federal supplemental at 22% is $79,200, California at 10.23% adds $36,800, Medicare at 1.45% adds $5,220, and Social Security (if below the wage base) adds $155. Sell-to-cover liquidates roughly 675 shares to cover, leaving 1,325 in the account.

Common mistake: assuming sell-to-cover eliminates tax exposure. The 22% federal supplemental rate undershoots a 32% or 35% bracket. A high earner exiting the year with $500,000 of RSU income has a five-figure shortfall at filing. Make an estimated payment or adjust W-4 withholding to close the gap.

Sell-to-cover matters at every vest date, in the quarterly tax planning cycle, and when coordinating a 10b5-1 plan that handles additional diversification sales.