The recession and high unemployment continue to take a toll in terms of declining membership, as the nation’s leading health insurers saw membership fall through the third quarter of 2009.

Between September 2008 and September 2009, the top eight carriers saw an aggregate decline of 1.7 million members, or 1.3%. Losses continue to be experienced in both the fully insured and ASO segments, according to Mark Farrah Associates, a leading provider of market data and intelligence solutions. ASO enrollment decreased by 1.1% and risk enrollment declined 1.6% for those plans.

The eight leading companies reported a combined loss of 860,000 members between the third and fourth quarters of 2009. Humana and Health Care Services Corp., which includes Blue Cross and Blue Shield plans in Illinois, New Mexico, Oklahoma and Texas, were the only organizations among the top eight plans to see enrollment gains in the third quarter. Humana was also among the few plans that saw year-to-date profit margin improvement compared with 2008.

In MFA’s latest “Healthcare Business Strategy” report, the firm reviewed enrollment and financial trends among eight top health insurers: Aetna, CIGNA, Health Care Service Corp., Health Net, Humana, Kaiser Permanente, UnitedHealth Group and WellPoint. These eight health plans cover nearly 60% of the total U.S. insured population.