By the time New Year's Day rolls around, UnitedHealthcare expects to have about 150,000 members from all over the country signed up for its group business health savings account. Even more in Tennessee will have joined up as individual members of the insurance giant's HSA. And there are some big expectations that the company is just getting started. "There's a very strong feeling that this is the way we need to go," said Roger Rollman, spokesman for UnitedHealthcare's Southeastern region, which includes Tennessee. "And President Bush is promoting it as well, along with the federal government." UnitedHealth representatives only began writing up new HSA members in mid-November, says Brian Shipp, the company's president and CEO for Tennessee and Arkansas. And it's been particularly popular with professionals in the area. "The cases we have sold so far have been professional organizations; a law firm, medical practices," says Shipp. "And we've had a lot of interest. All fully insured customers have wanted to look at a proposal. My gut instinct is that for the long term, I think it's a can't-miss." And HSAs may well prove successful in the short term, he adds, depending on the results for current renewal season and companies' timeline for transitioning into consumer-driven insurance. UnitedHealthcare is just one of 16 insurers to offer HSAs in Tennessee. In Mississippi, 11 HSAs have been promoting the new insurance package. A complete list can be seen at hsainsider.com. And the signs are growing that the new insurance product will soon grab a significant portion of the business. HSAs are structured very simply: Individuals and companies can set up accounts and contribute up to $2,600 for an individual or $5,150 for a family on a pre-tax basis. Companies, for example, may choose to contribute up to half of the money going into the HSA account. Individuals obtain a high-deductible insurance plan and use their contributions to pay for their regular medical needs, managing the costs themselves. The funds in the health savings accounts are invested and if there is money left over at the end of the year, it can roll over from year to year, building up to pay for extra medical costs in old age. Analysts see HSAs as an effective way for everyone to deal with high insurance premiums, which have been soaring at a double-digit pace for five years. This way, companies that can't afford insurance are also limited to a fixed annual contribution, with workers paying for any rise in premiums. Earlier this year, Mercer Human Resource Consulting completed a survey showing that three-quarters of respondents were either very likely (19 percent) or somewhat likely (54 percent) to offer a high-deductible health plan with an HSA by 2006. And companies at both ends of the spectrum are likely to jump first, with 81 percent of very large employers (20,000 or more employees) and 78 percent of very small employers (10-49 employees) very or somewhat likely to start by 2006. "We're looking at a major market change unlike anything we've seen before," says Linda Havlin, leader of Mercer's health care and group benefits consulting practice for the Midwest. "That so many employers - normally a cautious bunch - are ready to adopt a new form of health plan so quickly tells us three things," says Ms. Havlin. "First, these employers are desperate for a solution to rising health benefit costs. Second, the concept of consumerism resonates well as a strategy for improving cost awareness and accountability. And third, employers view the HSA as a vehicle for helping employees to save for post-retirement medical needs in the face of declining employer-sponsored coverage." But HSAs also have critics who say rewards have been overblown and many HSAs may have the opposite effect than what was intended: actually pushing some people to spend more on health care than they had in the past. "There's a lot of buzz from vendors and consultants about consumer-driven health plans, but many employers are skeptical about cost savings for their company," said Paul B. Ginsburg, Ph.D., president of Center for Studying Health System Change, a nonpartisan policy research organization funded principally by The Robert Wood Johnson Foundation. "Some have crunched the numbers for themselves and don't see the savings." In one case cited by Ginsburg, a company chief executive estimated that most of his workers spent $1,000 a year on medical expenses. If he gave them a thousand dollars towards an account, they would probably spend more, not less. Another noted that a third of his employees didn't have insurance with his company but got coverage through a spouse's job. In his case, HSAs would probably shift more coverage into his group, causing costs to go up.