The IRS's battle against identity theft has been successful, resulting in a significant decrease in fraudulent returns, officials said. 

“Through the first nine months of this year, that number is down by more than 50 percent,” he said, amounting to about 275,000 fewer taxpayer victims than there were a year ago, IRS Commissioner John Koskinen said at a Security Summit press briefing Thursday.

Koskinen attributed the decline in fraud to the agency's formation of the Security Summit Group in March 2015, an unprecedented partnership between the public and private sectors designed to crackdown on identity theft.

The IRS commissioner added that Summit Group has since grown significantly and its memorandum of understanding has now been signed by 40 states and 21 industry partners, as well as endorsed by seven major organizations in the tax and financial industries.