Membership, profits up for HMOs last year. (health maintenance organizations)

Despite a poor fourth quarter, Harvard Community Health Plan (HCHP) continued to hold its dominant position in the state's HMO market during 1991, posting a strong $13.6 million gain on revenue of more than $740 million, while increasing its size to nearly 440,000 members.

Pilgrim Health Care was the only other plan to earn more than $10 million for the year, but most industry players fared well nonetheless. Only four of the 18 Massachusetts-based HMOs found themselves in the red by year's end, according to figures obtained last week at the state's Division of Insurance.

Missing from the data were numbers for Tufts Associated Health Plans and Bay State Health Care. Tufts officials said their figures are not complete, while Bay State's results are being delayed following the major shakeup at the Cambridge-based plan in 1991. Company officials said a complete audit of Bay State's finances is currently being conducted. Bay State is likely to end up in the red when the audit is complete.

Elsewhere, the results revealed HMOs continuing to gain market share at the expense of indemnity plans--and gaining for that very reason, the …