Victor Fleischer, a law professor at the University of San Diego, is another who has recommended that the Treasury get rid of the unjust tax treatment on carried interest. Mr. Fleischer, a contributor to The New York Times, has also estimated how much money such a change would bring to the Treasury.

“It’s something that Obama could accomplish and, to be honest, I’m not entirely sure why the Treasury hasn’t taken an interest in it,” Mr. Fleischer said in an interview. “In fact, there is quite a bit of revenue at stake. And doing this on carried interest would cement Obama’s legacy in substance as well as symbolically.”

Rachel McCleery, a Treasury spokeswoman, said in a statement that closing the carried interest loophole has been a priority for the Obama administration from the outset and that the department is continuing to explore its existing authority for ways to address the loophole.

But the department cannot eliminate the carried interest tax benefit by itself, she contended.

“The president’s first budget in 2009 — and every one since — has included a proposal to close this unfair loophole and we’ve been pushing Congress to get it done,” she added. “No one should be able to play by a different set of rules, so it’s time for Congress to act to close the carried interest loophole once and for all.”

The provision has come under repeated political attack. During the current presidential campaign, all three remaining candidates — Bernie Sanders, Hillary Clinton and Donald Trump — have called for eliminating it. A number of lawmakers tried to get rid of the carried interest tax benefit beginning in 2007; by 2010, it looked as if the special treatment would go by the boards.

But a lobbying campaign by the financial industry, supported by a number of influential Republican lawmakers who argued that carried interest should be ended only as part of a broader tax overhaul, put a stop to the effort.

The Treasury’s recent action on corporate inversions is encouraging, Mr. Wilensky said. But he acknowledged that it was easier to get rid of a tax rule that benefits faceless corporations than it was to abolish a regulation that enriches a small group of extremely powerful and vocal people.