An alternative funding approach is where countries implement national health insurance by legislation requiring compulsory contributions to competing insurance funds. These funds (which may be run by public bodies, private for-profit companies, or private non-profit companies), must provide a minimum standard of coverage and are not allowed to discriminate between patients by charging different rates according to age, occupation, or previous health status (pre-existing medical conditions). To protect the interest of both patients and insurance companies, the government establishes an equalization pool to spread risks between the various funds.