The exclusion from income and payroll taxes for employer-paid health insurance premiums amounted to more than $240 billion in 2010. As policy-makers search for ways to pay for health care reform and contain health care costs, this exclusion is coming under scrutiny, despite the fact that employee-sponsored insurance (ESI) is an integral part of the health insurance system. This update of a 2003 synthesis looks at the tax subsidy for private health insurance. Key findings include: The current tax subsidy benefits higher-income workers the most. The tax exclusion is worth more to those in higher tax brackets, higher-income workers are three times more likely to work for firms who offer ESI than lower-income workers, and they are more likely to purchase ESI when offered because they can afford it. Families earning $10,000 to $20,000 annually spend more than 25 percent of their income on health insurance but the value of their tax subsidy is only $1,500. By contrast, earners over $200,000 spend less than 5 percent on health insurance but their benefit is worth $4,500. Workers who cannot afford ESI or are ineligible, including the self-employed and many part-time workers, do not receive this subsidy when they purchase private, non-group coverage.