Hawaii Medical Service Association, the state's largest health care insurer, is seeking an average 9.9 percent rate hike for its large employer groups that renew policies in January.

State Insurance Commissioner J.P. Schmidt said the independent Blue Cross Blue Shield affiliate has filed for approval of the rate increase, which affects only a portion of its membership.

HMSA has declined to release information about the rate requests, saying it will probably include it among other news it will report when it announces quarterly financial results later this month. HMSA is among health care plans requesting increases in rates for next year because of rising health care costs and lower returns from the investment of reserve funds.

HMSA did not give any details of how many members or companies would be affected by the rate request, which is split among several filings. The rate requests cover its so-called "merit-rated" groups, which usually have more than 100 members.

Last year its January round of merit-rated increases covered about 150 large businesses and 130,000 members. At that time the large group rates went up an average of 11.4 percent.

It's expected that HMSA will reference net losses it is sustaining when it eventually does make the filing information available. During the first half of this year, the nonprofit insurer lost about $30.7 million and has said it would probably record red ink during the remainder of the year.

Schmidt has 60 days to approve or reject the filing or ask for more information.

"We do take it very seriously," Schmidt said. "If they don't provide the facts and analysis that would justify the rate increase, we do not approve it."

But he also said his office understands insurers need to have rates approved quickly so they can inform customers of upcoming increases.

The Insurance Division also is considering a rate increase proposed by Kaiser Permanente Hawaii for 150,000 of its members. Schmidt said Kaiser has applied for a 12.3 percent increase, with the health plan saying the average rate increase passed on to members under the proposal is 10.7 percent.