They are not liable to you for anything. This did not affect your total tax liability or payments for the year: what you owe and have to pay in taxes is the same whether it is taken out every week and you owe nothing at year's end, or whether it is all paid at once at tax time. Only the timing of when you pay taxes, not the total amount you have to pay changes. If you had less taken out each week, that mean you had the money during the year and could have saved it to pay it now. But again, the total in-your-pocket income and total taxes owed are not affected by the withholding; only the timing of when you was altered. Since you did not actually lose any money by this, the employer is not liable.