America's Retail Workforce May Already Be Getting Squeezed By Obamacare

But this is even as employment in the retail sector posted strong gains in the second half of last year, according to Paul Ashworth at Capital Economics.

Typically, the two move in tandem.

Ashworth writes that this can be attributed to a specific part of the Affordable Care Act (Obamacare). From the start of 2014, employers with more than 50 employees will be fined $2,000 per employee, if they fail to offer full-time employees health insurance. Workers are considered to be full-time if they work over 30 hours a week.

"This effect could explain why average weekly hours worked in the retail sector has fallen over the past 12 months, while average hours worked across the private sector as a whole has been broadly unchanged," writes Ashworth. "The gap in relative performance only seemed to begin about 12 months ago."

Here are two charts that look at 1. average weekly hours worked in the retail sector and overall and 2. employment in retail sector and overall employment.

Ashworth writes that the reason a similar move hasn't been seen in the leisure and hospitality sector, is because the average weekly hours worked there are already below 30.