The overriding concern — for insurers, many workers and officials throughout the health care systems in many states — is the broad reductions proposed for Medicaid. Even for insurers that have largely abandoned the individual market, like UnitedHealth Group and Aetna, a substantial portion of their business is providing coverage under Medicaid. The same is true for many local nonprofit plans, said Ceci Connolly, the chief executive of the Alliance of Community Health Plans.Employers and others said they were also concerned about the effects on freelancers, who do not have a traditional employer but are self-employed or contract workers in the so-called gig economy.Depending on their income, those workers have shuttled between Medicaid and the individual insurance market under the federal health care law, which offered a greater level of stability, said Nell Abernathy, vice president for research and policy at the Roosevelt Institute, a left-leaning economic research organization.“A huge swath of Americans are in insecure work arrangements,” she said. “This repeals that level of security, which was not perfect, but it was a step in the right direction.”Small businesses, which were sharply divided over the original law, remained mixed in their response to the Republican bill, and there seemed little doubt that some companies would drop coverage in the absence of any penalty. The National Federation of Independent Business, which opposed the Affordable Care Act, said the House legislation was “a crucial first step toward health care reform.”In other people’s view, employees of small businesses would lose out if Medicaid were rolled back or the exchanges became threadbare, because many smaller companies rely on employees’ ability to obtain coverage through the government program or individual market.