HSAs are highly tax-advantaged savings vehicles that are most attractive to the high income and those with low health service use. They are unlikely to significantly decrease the number of uninsured, who often have low incomes, do not benefit significantly from the tax advantages, nor have assets to cover the large deductibles associated with the plans. Their ability to reduce system wide spending is also limited. HSAs have the potential to increase segmentation of health care risk in private insurance markets, unless employers set premiums to offset the healthier selection or government subsidizes the costs of the remaining comprehensive coverage market.