Even taxpayers who filed by April 15 may not be done wrangling with Uncle Sam any time soon.
The reason: They're amending their return. In most cases, the IRS gives taxpayers three years from the date they filed their original return, including extensions, to make changes. Regardless of what form you initially filed, and how, federal income tax amendments must be submitted via paper using form 1040X. Each state has its own forms and procedures.
"It's not extremely common, but it's certainly not rare, either," said Melissa Labant, director of tax advocacy for the American Institute of Certified Public Accountants. Last April, the IRS said it expected that almost 5 million taxpayers—about 4 percent of the 131.2 million returns received—would file an amended return.
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Although the IRS has not yet released estimates for this year, spokesman Eric Smith said it's likely to be a figure similar to last year's. "It's not unusual for there to be 3 to 4 percent of returns, sometimes a little more, amended in a given year," he said. By April 17, according to its latest report, the agency had received nearly 132.3 million individual returns, 0.8 percent more than last year.
"We have an amended return for the same reason pencils have erasers," said Smith. "We all make mistakes. … It's a mechanism to fix what's wrong."
Reasons why a taxpayer might amend an income tax return filed this year, or even in previous years, vary widely. Sometimes it's as simple as a 1099, K-1 or other tax form that arrives or is corrected after you've already filed, said Barbara Weltman, a tax and business attorney based in Vero Beach, Florida. Or maybe you realize you forgot to claim a valuable deduction. Worthless securities and bad debts also merit an amendment, she said—in which case, taxpayers have up to seven years to go back and claim the loss.
Other circumstances are tied to specific events and rule changes. For example, after the Treasury Department and the IRS ruled in 2013 that married same-sex couples would be treated as married for federal tax purposes, those couples could opt to amend returns filed up to three previous years. Victims of some natural disasters may also be able to amend their prior year's return to include the losses, said Smith, which can result in a faster refund than waiting until the next filing season.
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