IRS Commissioner John Koskinen said in an interview last week that 2015 could present a very difficult filing season because of uncertainty about expired tax provisions and the implementation of new rules under the Affordable Care Act (ACA) and the Foreign Account Tax Compliance Act (FATCA).

More than 50 provisions expired at the end of 2013 and haven't yet been extended. Congress is expected to return for a lame duck legislative session on Nov. 12 to address the provisions, but the outcome is still uncertain. See our Tax Legislative Update for an in-depth analysis of the legislative outlook and a table detailing the status of each expired provision.

Koskinen said late legislative action could delay the start of the filing season until the end of January. Taxpayers with returns affected by the expired provisions could be forced to wait even longer. He pointed to the 2013 filing season, when certain taxpayers couldn't begin filing until Feb. 14 because the IRS had to process all the changes from the last-minute "fiscal cliff" tax deal.

Koskinen predicted 2015 could be the most complicated filing season ever because the IRS is also implementing the ACA and FATCA. Each bill has numerous major provisions taking effect for the first time in 2014 and 2015. He has asked lawmakers to make any legislative changes as quickly as possible.

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