WASHINGTON—Elon Musk gave new fuel to GOP critics of the Republicans’ multitrillion-dollar tax and spending agenda, saying that the current measure failed to reduce the federal deficit, echoing complaints from hard-line factions in both the House and the Senate.

Billionaire Elon Musk has criticized President Donald Trump's "big, beautiful" tax and spending bill, saying it detracts from his efforts to shrink the U.S. budget deficit.