The Treasury Inspector General for Tax Administration reports that more than 15 million people could owe more income tax than usual next April, thanks to the 2009 stimulus act’s Making Work Pay credit (MWP). New withholding tables accommodating the credit are overly generous to people who work multiple jobs, pension recipients, and two-earner couples. For them, withheld taxes will drop more than the credit will cut what they owe the IRS.