See here for one such example: https://pnhp.org/news/impact-of-aca-on-employers-and-their-e...
Some relevant highlights: * More than one-third of organizations now have increased out-of-pocket limits, in-network deductibles and/or participants’ share of premium costs in response to ACA. More than one in five organizations have increased copayments or coinsurance for primary care, increased participants’ share of prescription drug costs and/or increased the employee proportion of dependent coverage cost. * The excise tax on high-cost group health plans (a.k.a. Cadillac tax) is considered the top ACA cost driver beyond 2015. Since 2011, a steadily increasing percentage of organizations has taken action to avoid triggering the excise tax — a trend likely to continue. More than one in ten organizations already have adopted changes to prevent them from triggering the tax, 21% are working on changes and 28% plan to act sometime prior to 2018. Only one-quarter said changes were not necessary either because they have no high-cost plans (23%) or because they plan to pay the tax (2%).
That being said, the year following the passage of the ACA saw a large anomalous spike in employer healthcare costs that wasn't present in Medicaid/Medicare. It's almost undeniable that this was due to the ACA.