SummaryAssuming symmetric information, we show that a high‐deductible health plan (HDHP) combined with a tax‐favored health savings account (HSA) induces more savings and less treatment compared with a full coverage plan under reasonable risk preferences. Furthermore, a higher tax subsidy increases savings in any case but decreases medical utilization if and only if treatment expenses are above the deductible. A larger deductible increases savings but does not necessarily decrease healthcare utilization.Whether an HDHP/HSA combination is preferred over a full coverage contract depends on absolute risk aversion. A higher tax advantage increases the attractiveness of an HDHP/HSA combination, whereas the effects of changes in the deductible are ambiguous. The paper shows that a potential regulator needs to carefully set the size of the deductible as only in a certain corridor of the probability of sickness, its effect on aggregate healthcare costs are unambiguously favorable. Copyright © 2015 John Wiley & Sons, Ltd.