A growing number Wall Street economists are downgrading their expectations for first quarter U.S. growth, after a sharp drop in December’s retail figures suggested consumers could be losing their enthusiasm to keep spending.

On Monday, the Commerce Department reported that retail sales in January rose by a better-than-expected 1.1%, rebounding from the prior month’s 1.6% drop — which was revised downward from an initial estimate of a 1.2% decline. The nearly $21 trillion U.S. economy relies heavily on consumer spending, which comprises about ⅔ of gross domestic product.

The unexpected cut to December’s figures, which occurred during the height of the holiday shopping season, prompted a number of economy watchers to temper expectations for growth during the first three months of the year.

“From a broader growth perspective, there is no doubt that Q1 GDP is tracking very weak,” Goldman Sachs said on Monday, estimating that the retail data suggested a first quarter growth rate of 0.5% “But timelier indicators of activity are improving gradually,” the bank added.

“The bigger concern is that, even allowing for further gains in February and March, [consumer spending] is likely to remain unusually weak in the first quarter,” Andrew Hunter, senior U.S. economist at Capital Economics, wrote in a research note to clients on Monday.

“Along with the decline in vehicle sales, that suggests real consumption growth is on course to slow further in the first quarter, supporting our forecast that overall GDP growth will slow to below its 2% potential pace,” Hunter added.

Analysts at JPMorgan Chase were even more bearish. The bank told its clients that “fundamentally, we still believe the consumer outlook is reasonably solid,” but added that softer retail data hinted that GDP would check in at 1.5% in the first quarter, an estimate still subject to “downside risk.”

The softer December’s figures could mean that the final three months of 2018 ended on a slightly weaker note than government data first showed, JPMorgan wrote.

Last month, the Atlanta Federal Reserve forecasted that fourth quarter 2018 growth would fall under 2% — well below the government’s initial estimate of 2.7% and short of President Donald Trump’s self-imposed target of 3%.

“The weakness in December sales coincided with a period of asset market losses and weak consumer sentiment amid government shutdown concerns,” economists at Barclays Capital wrote on Monday, adding that post-Thanksgiving Black Friday sales may have cannibalized some of December’s consumer activity.