President Donald Trump said he’s considering a capital gains tax break by issuing a regulation that would index gains to inflation.

“I’m thinking about it,” Trump said Thursday in an Oval Office interview with Bloomberg News.

In the wide-ranging interview he also expressed support for Fed Chairman Jerome Powell and said embattled Attorney General Jeff Sessions would not leave his job before the midterm elections.

He also threatened to withdraw from the World Trade Organization, said the U.S. may be close to a new trade deal with Canada, and rejected a European proposal to eliminate tariffs on automobiles.

The capital gains change would slash tax bills for investors when selling assets they have such as stock or real estate by adjusting the original purchase price for inflation. The change has been a longtime goal of Trump’s top economic adviser, Larry Kudlow, who says the policy would spur job creation and economic growth because people wouldn’t be taxed on phantom income.

The issue has been gaining attention since Treasury Secretary Steven Mnuchin said in July that his department was looking at whether it could sidestep Congress and issue a rule to allow capital gains to be indexed to inflation.

Still, the move is likely to face legal challenges from critics who say it gives an unfair advantage to investment income and from those who say it needs Congressional sign off. It could also alienate some segments of Trump’s base, as it would mostly benefit top earners who have investment income.

The inflation adjustment would amount to a several percentage point tax cut for investors, depending on the type of asset and how long it’s held for, according to estimates from the non-partisan Congressional Research Service. Corporate stock with dividends held for 10 years would be subject to an effective tax rate of 24.3 percent under current law. That same holding indexed to inflation would be subject to a 21.4 percent tax rate, the group said.

Other highlights from the Bloomberg Interview included:

On pulling out of the WTO: “If they don’t shape up, I would withdraw from the WTO.”

On Sessions, Trump said his job is safe until after the elections. “I just would love to have him do a great job.”

On Powell, whose Fed has been a target of Trump criticism over interest rate increases: “I put a man in there who I like and respect.”

On a trade deal with Canada, he said he thought it was close: “It may be by Friday or it may be within a period of time. But ultimately they have no choice.”

On the EU’s proposal to eliminate auto tariffs, he said: “It’s not good enough.”

It’s debatable whether Trump can cut capital gains taxes unilaterally. President George H. W. Bush’s administration considered allowing gains to be indexed to inflation through regulation without Congress, but ultimately dropped the idea.

The House Ways and Means Committee is planning to release legislation outlining a second round of tax cuts in September. Kudlow has pushed for capital gains indexing to be included in that package. Representative Kevin Brady, the committee chairman, has said he doesn’t intend to include that provision in the bill — but he’s signaled he’s open to Treasury proceeding on its own.