President Trump promised that his tax cut would encourage companies to invest in factories, workers and wages, setting off a spending spree that would reinvigorate the American economy.

Companies have announced plans for some of those investments. But so far, companies are using much of the money for something with a more narrow benefit: buying their own shares.

Those so-called buybacks are good for shareholders, including the senior executives who tend to be big owners of their companies’ stock. A company purchasing its own shares is a time-tested way to bolster its stock price.

But the purchases can come at the expense of investments in things like hiring, research and development and building new plants — the sort of investments that directly help the overall economy. The buybacks are also most likely to worsen economic inequality because the benefits of stocks purchases flow disproportionately to the richest Americans.