I'm not sure what you mean by "claiming zero." Withholding allowances were eliminated from Form W-4 five years ago. You no longer "claim 0" or any other number of allowances. The new form works differently. As a guess, the problem might be that you are not accounting for the fact that you both work. You can use the Tax Withholding Estimator on the IRS web site to figure out what you and your wife should each put on the W-4 forms that you give to your employers. It will show you how to adjust your withholding to get the approximate refund amount that you want.
