Lastly, because you may have a lump sum of income that has no federal tax withheld, you should plan to make an estimated tax payment as soon as you can, probably 22%-36% of the amount, depending on your total income. Even then, you might owe a penalty for underpayment. If the IRS does assess a penalty for underpayment, you can ask for a waiver when that happens.
Estimated payments can be made at www.irs.gov/payments.
