What gets withheld on a vest rarely matches what's owed.

Restricted stock and other supplemental wages are withheld at a flat 22% federal rate, set by Treasury regulation — not at the rate your income is actually taxed. For high earners the real marginal rate is often 32 to 37%. The gap can surface as a balance due the following April. Answer a few questions and see, in plain terms, where you may land.