Coremark Insurance recently put out a brief blog post about the Affordable Care Act and Staffing Companies that reminds how co-employment liability can be spread amongst BOTH client companies and the staffing company employing the worker. The following quote [ALONG WITH MY COMMENTS IN CAPS] from the blog post helps to sum up the potential liabilities.
Because employers [AKA CLIENT COMPANIES] do not offer health coverage to workers supplied by staffing agencies, if the IRS decides to classify them as common law employees it could trigger liability ACA penalties [FOR THE CLIENT].
See the full article Staffing Agency and Temp Workers and Your ACA Obligations here.
Below is an Infographic providing more information on the basics of the ACA: