A number of hospital systems got into the business of insurance back in the '90s when HMOs were popular. Most found it hard to manage the financial risks involved in managing an insurance plan. But analysts say this time hospitals may have better tools to help them make it work.  "Since we've moved through the 2000s and into the current day, the data capabilities are much greater, and many hospitals are much more closely aligned with their physicians than they had been in the past, " said Lisa Martin, senior vice president at Moody's. "But there certainly are still those risks that were present back in the '90s."  One risk for North Shore-LIJ's CareConnect is that it may have priced its premiums too low. As a new insurer, it doesn't have historical data on how much medical care its members typically use. And under the ACA, insurers can no longer charge higher premiums for those with pre-existing conditions who may need more medical care.  (Read more: WellPoint says exchange enrollment ahead of plan)  While an insurance plan can help boost revenue at a time when insurers are pushing back at hospitals on reimbursement rates, it can also backfire because it puts the hospital in direct competition with other insurers.  "That really changes the dynamics of that relationship. So if it's not managed well," explained Martin, "in an extreme case that can result in a termination of that relationship, and the hospital can lose patients."  At this point CareConnect's CEO is optimistic about managing the insurance side of the business, after having exceeded early enrollment expectations.  "We thought that we would probably have 3,000 to 4,000 individual members—of which, 50 to 60 percent of them would actually pay the bill," said Murray. "We've had almost double that—on and off the exchange."  Mike Perivolaris has written the check for his company's premium, and he's hopeful his gamble on the new insurer will pay off.  "We try new things every day," he said. "We're business owners. So, we have to be a little bit daring sometimes to make good decisions."  —By CNBC's Bertha Coombs. Follow her on Twitter @berthacoombs .
North Shore LIJ's first foray into the insurance business is going smoothly so far, helped by its well-established reputation.