The numbers: A survey of American manufacturers showed the slowest growth in December in 15 months, reflecting a dip in confidence among executives about how their businesses will perform in the new year.

IHS Markit said its manufacturing PMI slipped to 53.8 in December from an initial reading of 53.9, and it was down from 55.3 in the prior month.

Any number above 50 indicates more companies are growing instead of shrinking, but the index has now fallen to its lowest point since September 2017.

That could be an ominous sign for the economy if the loss of confidence continues to spread. The level of optimism among senior executives was at the lowest ebb in more than two years.

What happened: The growth in new orders and employment both slowed in December, though production remained the same as in the prior month. Exports also grew faster.

Somewhat slower business expansion has resulted in one unintended benefit: Inflationary pressures eased again to an 11-month low.

The big picture: The Markit survey of the U.S. manufacturers paints a somewhat darker view than other reports such as the Institute for Supply Management or Chicago PMI. By and large the U.S. economy is still expanding at a healthy pace outside of a few areas such as housing.

The rest of the world, however, is not faring as well and worries about the global economy appear to influencing how American companies view the future of the economy. Most economists predict the U.S. will decelerate in 2019.

Also see:China’s manufacturing activity hits 2-year low

What they are saying: “Manufacturers reported a weakened pace of expansion at the end of 2018, and grew less upbeat about prospects for 2019,” said Chris Williamson, chief business economist at IHS Markit. “The survey also revealed signs of slower demand growth from customers, as well as rising concerns over the impact of tariffs.”

Market reaction: After a rocky start, the Dow Jones Industrial Average DJIA, +0.13% and S&P 500 SPX, -0.46% both rose in the first trading session of 2019 despite renewed worries about a global economic slowdown.