don't now yalls language. so i can't say . but at spirit we could put the bonus monies into the 401k. the max this year is $19k. IRS doesn't care if it comes from bonus or salary. 19K is 19K . regardless of 'withholding rate' of bonus at the end of the year your tax rate is based off your taxable income. If you are short, you owe money. If you paid too much, you get a refund.