Most economists think the U.S. will experience somewhat stronger growth in the coming years due to recent legislation that relaxed postcrisis rules on some banks, though a sizable minority said the measure could at least modestly weaken financial stability.

Among dozens of forecasters surveyed in recent days by The Wall Street Journal, 61% said they expected U.S. growth in the medium term would be modestly stronger thanks to the bill signed last month by President Donald Trump. Some 33% said they expected no effect on economic...