A recent wave of stock buybacks by large U.S. companies is likely to prompt shareholders to expect more in future years, possibly impeding a company's ability to pay down its debts, according to a report by Moody's Investors Service Inc.

Multinationals pivoted in the second half of last year to using cash freed up by the 2017 tax-code overhaul for share repurchases, instead of paying down debt, which they had done for the first six months of the year.

The shift away from “credit-positive activities such as debt reduction” toward returning cash to shareholders through share repurchases suggests that the benefits of President Donald Trump's tax law “may be losing steam,” said the report, issued Tuesday. That's in part because loading up on debt can impede a company's cash flow and ability to repurchase shares just as investors demand more of that.