In California, are employers required to withhold income taxes on bonuses?

Last year I received a bonus with no state or federal income taxes withheld and now my tax bill is obviously more than I would like. If the answer is yes, please state your source so I can look into it further.

Public Comments

1. Yes, employers are required to withhold tax on bonuses. Federal income tax must be withheld at 25%, plus FICA and Med. CA requires withholding at 9% or 10% if memory serves correctly. You should have challenged this at the time the bonus was paid, as it was clearly illegal. The Fed reference is Pub 15, aka Circular E which governs all Federal withholdings. I don't have the FTB ref handy but it is similar. However there's nothing that you can do, aside from file a formal complaint against your employer. You still owe the tax. You also had the opportunity to make estimated payments of the tax at the time (or at least set aside enough to pay the eventual bill) but failed to do so. This puts you on an even footing with your employer as far as not acting properly or prudently in the matter. Comment on Russ' answer: If you're self-employed and your income is documented on Form 1099 then you're not an employee. In that case, no taxes are withheld from any of the monies paid. I stand on the statutory 25% Federal income tax withholding requirement on bonuses and other irregular payments paid to EMPLPOYEES. It's well documented in Pub 15.
2. If your are an employee, it doesn't matter what state you live in they should have taken out taxes on a bonus. Have you asked the company why it was handled this way? Did they issue you a 1099? If so this is a problem for the company. There are only two legal ways to calculate the federal withholding on a bonus (I would have to look up the percentages for California). The first way is to withhold 20% plus FICA/SS. The second way is recalculate the last paycheck before the bonus and then withhold taxes according to the tax tables and of course Fica/SS. The sources of this information are a bit harder to answer. I have been a certified tax professional for 18+ years and before that I managed a corporation for 13 years. I had a very good teacher...he worked for the IRS and even helped write some government accounting prodecures. So, all of that means that it isn't one tax law that will give you the correct answer. It is a combination of several. Hope this helps EDIT: Bostonia's answer isn't totally correct. If it is shown that the company treated you as an contract employee when you were in fact an employee. Then the tax liability is the companies. And, the only way for the company to avoid that is if they prove you paid taxes on that amount. And, the IRS will not help them, you would have to share that information with them! Again, hope this helps!
3. regardless...you owe the tax. i know that now it seems like a burden, but it would have been the exact same burden if the tax was withheld at the time you received the bonus. well, ok now there may be a penalty.
4. Yes, they should have. If they didn't, they were in error. However, you are still responsible for all taxes owed.