The Internal Revenue Service is intensifying its scrutiny of wealthy Americans.
The federal agency increased its audits of taxpayers who earned $1 million to $5 million by 33 percent last year compared with 2008, new I.R.S. figures show.
The numbers, released late Thursday in the agency’s 2009 annual data book, also show that the I.R.S. increased its audits by 16 percent for those earning $5 million to $10 million last year. Audits of those who made at least $10 million rose by 8.5 percent, according to the data.
The figures are the strongest evidence yet that the agency is honoring a vow by the I.R.S. commissioner, Douglas H. Shulman, to increase scrutiny of wealthy taxpayers.
Taxpayers who earned at least $1 million a year made up 0.25 percent of the more than 144 million individual federal returns filed last year, the data showed, but affluent Americans account for a far greater share of the underpayments in federal income tax returns.
“The 2009 results show our emphasis on higher-income individuals,” Bruce I. Friedland, an I.R.S. spokesman, said Friday in a statement. “We will continue to focus our enforcement efforts on high-income taxpayers, particularly those hiding their assets overseas.”
Tax specialists said Friday that the new data showed a surprisingly strong increase in the agency’s scrutiny of the affluent. “There is definitely a new focus on what we call high-dollar audits,” said Richard Boggs, the chief executive of Nationwide Tax Relief, a company in Los Angeles that helps taxpayers negotiate settlements of tax bills with the I.R.S.
“The I.R.S. is getting smart,” he said. “They are starting to better leverage their time, resources and talent in order to collect the most money. There is a definite shifting of the tide.” He said audits of those making at least $10 million rose slightly less than for other categories because so many of the ultrawealthy were already being audited.
Mr. Boggs said the 2009 I.R.S. data showed that taxpayers who made at least $1 million had an 8 percent chance of being audited last year, meaning about one out of every 12 was scrutinized — up from 6 percent in 2008, or nearly one in 17.
The I.R.S. created the Global High Wealth Industry Group last fall to scrutinize people earning at least $10 million a year. It focuses on deciphering the techniques the wealthy sometimes use to illegally minimize their tax bills. Those techniques include the use of partnerships, trusts and offshore entities.
The I.R.S. is also sorting through more than 15,000 disclosures filed by wealthy taxpayers last fall as part of an amnesty program aimed at luring out of hiding taxpayers who had not reported income hidden overseas.