You may remember the name Sheldon Adelson from the 2012 election. He was the casino mogul who donated $20 million to Newt Gingrich’s campaign. He’s been a generous donor to other conservative groups and causes. He donated at least $53 million in the last election, according to Forbes. Other sources put the figure even higher. He was a big conservative donor in 2008, too.

And, as it turns out, he has been put under a microscope by the Internal Revenue Service as well. The Sunlight Foundation, a nonprofit investigative journalism group, reported last year:

Billionaire casino mogul Sheldon Adelson and his wife, Miriam, who have reportedly given a combined $10 million to Winning Our Future, the super PAC that supports and is run by former staffers of Republican presidential candidate Newt Gingrich, were drawn to him by a shared view of the importance of the U.S. relationship to Israel.

But a review of public records by Sunlight suggests that the couple, who appears to be the former House speaker’s most generous political patrons pending the filing of Winning Our Future’s first complete financial disclosures later this month with the Federal Election Commission, have considerable financial interests involved in battles with the federal government that Gingrich is vying to head:

Adelson’s company, the Las Vegas Sands, disclosed in its most recent Securities and Exchange Commission quarterly report that it appealed the results of an Internal Revenue Service audit for the company’s 2005 to 2008 tax returns. The audit may result in as much as $23 million in additional tax payments, although the final amount, the company concedes, is “inherently uncertain.” The IRS also audited Las Vegas Sands’ 2009, and recommended additional payments.

The disclosure linked above in the foundation’s story stated:

In 2010, the Internal Revenue Service (“IRS”) issued a Revenue Agent’s Report (“RAR”) for tax years 2005 through 2008 of which the Company is appealing certain adjustments proposed by the IRS. The Company is in the initial stages of the appeals process with the IRS and while the final outcome of these matters is inherently uncertain, the Company believes it is reasonably possible that the total amount of unrecognized tax benefits may decrease by a range between $0 and $23 million within the next twelve months primarily due to the possible settlement of matters presently under consideration at appeals. During the three months ended September 30, 2011, the IRS completed its field examination of the Company’s 2009 income tax return and issued an RAR proposing certain adjustments that the Company is currently evaluating.

The fact that Adelson’s business was scrutinized does not prove anything untoward or unethical was done. Checking returns is, after all, what the IRS does, and Adelson owns some big, high-profile businesses.  But give the recent revelations regarding the IRS, at this point you do sort of have to wonder.