Massachusetts employers gave a big “Bah Humbug” to the year-end economy as business confidence withered in the face of a government shutdown and the largest one-month stock market decline since the Great Depression.

The Associated Industries of Massachusetts Business Confidence Index (BCI) lost three points to 58.6 during December, its lowest level since December 2016. Confidence readings have dropped five points during the past 12 months.

The retreat was led by an 8.6-point drop in employer views of the national economy, and a 4.7-point drop among manufacturing companies.

Overall confidence remains within optimistic territory, but less comfortably so than earlier in 2018.

“The Massachusetts economy remains strong, with a 3.3 percent growth rate and an unemployment rate of 3.4 percent, but employers are increasingly concerned about factors such as financial-market volatility, a dysfunctional national political debate and challenges such as the cost of providing health insurance to employees,” said Raymond G. Torto, Chair of AIM’s Board of Economic Advisors (BEA) and Lecturer, Harvard Graduate School of Design.

One employer who participated in the survey summarized the uncertainty: “A tremendous amount of unknowns are ahead.”

The AIM Index, based on a survey of Massachusetts employers, has appeared monthly since July 1991. It is calculated on a 100-point scale, with 50 as neutral; a reading above 50 is positive, while below 50 is negative. The Index reached its historic high of 68.5 on two occasions in 1997-98, and its all-time low of 33.3 in February 2009.

The Index has remained above 50 since October 2013.

Constituent Indicators Lower

The constituent indicators that make up the overall Business Confidence Index were mostly lower during December.

The Massachusetts Index assessing business conditions within the commonwealth lost 2.4 points to 64.7, leaving it 2.9 points lower than in December 2017.

The 8.6-point decline in the U.S. Index to 55.1 left employer sentiment about the national economy 9.1 points lower than a year earlier. It marked the lowest reading for the U.S. Index since May 2017.

The Company Index measuring employer assessments of their own operations dropped 1.4 points to 57.8, down 4.3 points year-to-year. The Employment Index gained 1.2 points to 54.4 during the month, leaving it down a modest 2.3 points for the year, while the Sales Index declined 1.6 points in December.

Employers don’t expect to change their outlook anytime soon.

The Current Index, which assesses overall business conditions at the time of the survey, fell 2.6 points last month to 60.0. But the Future Index, measuring expectations for six months out, dropped 3.4 points for the month and 7.2 points for the year.

Non-Manufacturers (59.4) were slightly more optimistic than manufacturing companies (57.7), re-establishing a trend that existed for most of 2018. Large companies (60.5) registered higher confidence readings than medium-sized companies (57.3) and small companies (57.7). Companies in Eastern Massachusetts (59.8) were more bullish than those in the west (57.0).

Paul Bolger, President of Massachusetts Capital Resource Company and a member of the BEA, suggested that uncertainty about economic factors such as slowing corporate profits, rising interest rates, and trade are overshadowing employer confidence in what remains a fundamentally strong growth pattern.

“Employers are cautiously watching earnings warnings from Apple and other major brands, while hoping that negotiations between the US and China are able to ratchet down the trade war,” Bolger said.

Eye on Health Costs

AIM President and CEO Richard C. Lord, also BEA member, said moderating the cost of providing health insurance to employees remains the biggest concern for employers who participated in AIM’s biennial Issues Survey in the fall.

That’s one reason, Lord said, that AIM has called upon the Legislature and Governor Charlie Baker to end immediately the two-year assessment imposed on employers last year to close a financial gap at the state’s MassHealth insurance program for low-income residents.

“The assessment is no longer necessary because employers last year paid tens of millions of dollars more than anticipated under the levy. Businesses are on track to contribute some $519 million by the time the assessment sunsets at the end of this year instead of the $400 million envisioned under the 2017 legislation,” Lord said.