Boring but important

The Treasury Department is considering a tax change that would cut the wealthiest Americans’ bills by $10 billion annually without going to Congress for approval. The agency is studying whether to adjust for inflation when taxing capital gains—the income from investments. It’s a move Republicans have endorsed for years but that’s almost certain to spark a legal challenge. The department has long believed it lacks authority to make such a change, but Treasury Secretary Steve Mnuchin says he would consider it if it can’t get done through legislation. Last year’s tax cut left capital gains rates for upper-income taxpayers untouched, disappointing some Republicans. Taxing only post-inflation gains would most benefit people with large investment portfolios.