Time is running out for a popular tax provision that allows owners of individual retirement accounts (IRA) who are 70½ or older to save on taxes when donating to charity.

The provision, which expires Dec. 31 (though Congress could reauthorize it), allows individuals ages 70½ or older to donate up to $100,000 of IRA assets to charity without reporting the withdrawal as taxable income. By reducing taxable income, the provision can help retirees avoid or reduce a host of taxes and penalties—including many tax increases that took effect this year. It can also count toward the annual required minimum distribution that people 70½ or older must take from a traditional IRA.

Unfortunately..it can't be done from your 401k.