Updated results from our Health Insurance Policy Simulation model show that, contrary to critics' claims, the law has a negligible impact on total employer-sponsored coverage and costs, leaves large business costs-per-person-insured largely untouched and makes small businesses-for whom coverage expands the most-financially better off, through tax credits and market efficiencies that lower premiums. Only among mid-size businesses does the ACA noticeably increase costs, largely due to increased enrollment. Our simulation does not reflect ACA cost containment provisions that may contain private as well as public cost growth-potentially slowing the decline of employer-sponsored health insurance that has been occurring for more than a decade.