Re: Paying Bonuses at year end
There is a rule for accrued bonus but as far as I can tell, it is 2.5 months and only available to companies on accrual basis. Even then the employee is taxed on the bonus not yet received so it has to be included in 2018 W-2 with a flat 22% FWT taken out (and paid). Your accountant is thinking because W-2's are not due until 1/31 that this 1/15 rule (that cannot be found in a general search) meets the time factor.
Before you include the bonus in the W2 but pay it next year have your accountant produce the IRS white paper regarding the subject and post us a copy