In addition to an individual mandate to carry health insurance, employers have a mandate to provide it. However, in recognition that it's difficult for small businesses to obtain and provide affordable health insurance, the plan exempts companies with fewer than 50 employees from the requirement. Small businesses, with fewer than 25 employees and an average wage of less than $50,000, will be eligible for subsidies for insurance just as individuals are, should they elect to provide it [source: Miller]. If a small business decides not to provide insurance, those individuals can enter the exchange.
As for businesses with more than 50 employees, if they don't provide health insurance for their employees, they'll be subject to an annual fine of $2,000 per worker (though the first 30 workers aren't factored into the fine). Companies with more than 200 employees must automatically enroll employees into their insurance programs. If you're receiving coverage from a spouse, you'll have to take the initiative to opt out yourself.
If you have insurance from your employer, and you're still spending more than 9.5 percent of your income on premiums, you'll be eligible to enter the marketplace as well [source: Grier]. You'll receive a voucher from your employer and enter the marketplace; the Department of Health and Human Services would determine if you were eligible for any additional subsidies.