The top 10 providers of Health Savings Accounts are making ground in improving the transparency, pricing, and structure of their products but still have room to grow as the market does, according to new analysis from Morningstar. In its second annual report of the $51 billion in HSA market, Morningstar rates the largest providers' products offered through the individual health care market—products tied to high-deductible health plans in the employer group market are not evaluated. The HSAs were evaluated by their effectiveness as spending vehicles—how the tax-advantaged products are designed to pay down qualified out-of-pocket medical expenses—and how they stack up as investment vehicles that cover future costs. "Overall, we find that the HSA plans we evaluated have mostly improved their quality of investments and investment menu designs since last year," writes Leo Acheson, associate director, multi-asset and alternative strategies at Morningstar. "Still, no plan earns positive marks across the board for use as a spending or investing vehicle, indicating continued room for improvement," added Acheson, author of the report. In terms of spending vehicles, Morningstar rates the fees on HSA checking accounts and the interest rate paid on cash deferrals. As investment vehicles, Morningstar measures the quality of investment lineups, the price and performance of investment offerings, and cash thresholds providers put on money that must first placed in an HSA checking account before it can be invested in mutual funds. Overall, investment quality and plan design have improved since last year, the report says. Half of the investment options offered by the 10 providers merit a gold, silver, or bronze Morningstar rating. And providers have reduced investment overlap in menus, and continued to add core investment options common in 401(k)s. But "transparency remains poor," according to Morningstar's analysis. Only four providers disclose investment fees and interest rates on cash accounts on their websites. And researchers found that call centers failed to provide basic information on the accounts. Fees on investments "remain elevated," the report says. The average cost of passive funds ranges from 30 basis points to 75 basis points. The average cost of active funds ranges from 80 basis points to 120 basis points. Eight of the providers require account holders to keep up to $2,000 in cash accounts before they can invest contributions. The average investor has about that much in their account. READ MORE: 10 HSA questions employers and employees ask Advisors see HSAs as opportunity Are HSAs worth the effort for TPAs?