Consumer spending is showing signs of slowing, specifically among low-income Americans, which is a concerning sign for the economy, reports the Washington Post.

Spending at U.S. retailers jumped 0.6% last month, more than double economists’ expectations of 0.2%, according to commerce data released earlier this week. But consumers in the top 10% of the income distribution accounted for 49% of total spending in the second quarter, the highest level it’s been since Moody’s Analytics started collecting this information in 1989.

“U.S. consumer spending is not just softening overall, it’s doing so in a fragmented way … and that’s a real problem,” Claire Li, a Moody’s vice president of credit strategy, told the Post.

“If the benefits and the pressures are not shared broadly, then we’re not looking at a balanced or a healthy state of the U.S. consumer base.”

Mark Zandi, chief economist at Moody’s Analytics, told CNN the economy’s prospects “are tethered to the fortunes and spending of the well-to-do.

“If [the top-earners] turn more cautious in their spending, for whatever reason, the economy will suffer a recession,” he said. That could happen if there were a significant correction in stock prices, he added.