The Hawaii Medical Service Association posted a $15.9 million profit in the second quarter largely on the strength of its investment gains.

The bottom line of the state’s largest health insurer, however, dropped from $21.8 million in the year-earlier period.

“If you ignore our investment earnings, you’ll see that we would have come very close to breaking even this quarter,” Steve Van Ribbink, HMSA’s chief financial and services officer and treasurer, said Friday in a press release. “Since we’re a nonprofit, breaking even is our goal. We only want to collect enough from our members to cover their health care benefits, plus the cost of administering those benefits.”

HMSA, which raised rates July 1 by an average 7.6 percent for about 7,400 small-business groups that cover 62,000 members, collected $748.8 million in premiums versus $730.4 million in the year-earlier period and spent $693.9 million on medical benefits compared with $652.3 million in the second quarter of 2014.

The cost to administer benefits rose to $62.7 million — 8.3 percent of revenue — from $54.8 million in the year-ago quarter. The result was an operating loss of $5.4 million compared with a gain of $17 million a year ago. The insurer adjusted its books to reflect a loss of $2.5 million for Affordable Care Act fees and taxes, which were less than anticipated. Investment gains jumped to $16.2 million from $4.8 million a year ago.

“Our employees take pride in delivering outstanding value to our members and the community,” Van Ribbink said, adding that the insurer is investing significantly in well-being programs such as health coaching, workshops and education to reduce chronic diseases as part of HMSA’s long-term vision to improve health care.

“While we can’t control the costs of expensive prescription drugs or treatment options, by working together, we can reduce the need for them,” he said.

HMSA’s membership totaled 726,350 at the end of the quarter, and it had $348 million in reserves, or $479 per member per month.