Employers are seeing health maintenance organizations asking to increase 2009 premiums 12%.

Researchers at Hewitt Associates L.L.C., Lincolnshire, Ill., have based that estimate on data for 160 large employers with about 1 million participants.

A year ago, HMOs were asking for an average premium rate increase of 12%.

Employers held the actual average 2008 increase to 9.4% through plan changes, negotiations and terminations, the Hewitt researchers report.

One way employers are holding down their costs is to make employees pay more to insure dependents, and by running audits to see whether some insureds covered as dependents really qualify for dependent coverage, the researchers report.