There are taxes, fines and penalties assessed on employers with fifty or more employees which do not provide health insurance for those employees. Under the new health care law recently passed, large employers have a duty to provide their employees with health care coverage or suffer the wrath of regulatory enforcement.
No employer is currently required to provide insurance for their employees. This does not matter whether the company has 50 or more employees or one employee. This will change in 2015 due to changes in the law. However currently no large businesses are required to pay for any kind of insurance for their employees.