Companies that are not confident tend not to hire workers. Now Obamacare is rendering many US mid-sized less confident than they would like to be, or that the struggling economy needs them to be, according to MarketWatch.

Consider a new survey of midsized companies (annual revenue of $10 million to $1 billion). The quarterly report found that nearly nine of every 10 firms expect health-care costs to be “somewhat challenging” or “highly challenging” in 2014, in no small part because of the rollout of the new law.

How big of a problem? Hard to say. Most companies of all sizes  have complained about health-care costs for years – it’s been repeatedly flagged as a top concern by the so-called Middle Market Indicator. The survey is conducted each quarter by the Fisher College of Business at Ohio State University, with funding by GE Capital.

Yet the latest results suggest the worries might be more acute, potentially causing a slowdown in hiring. The survey shows companies plan to increase “mean” employment by 2.2% in 2014 vs. 2.5% in 2013.

“A majority of middle-market companies said that uncertainty around government policies is impeding their ability to grow and their willingness to hire and spend,” the survey found. “The impact of healthcare legislation continues to be the largest concern.”

If those concerns turn out to be well-founded, it might suggest little change in the pace of net job growth in 2014. Midsized firms may have accounted for roughly half of the 2.1 million jobs created in 2013.

Overall these mid-sized companies remain “optimistic” about 2014, but if they’re not hiring and some may even be laying workers off or reducing hours due to Obamacare, that optimism won’t mean much.