The sector headed into 2011 uncertain about how a new health care overhaul rule governing medical-loss ratios — essentially the percentage of premiums insurers spend on care — would affect their business. The impact of that rule turned out to be manageable, and companies are moving toward 2012 with health care use continuing to grow at lower rates than they expected, which helps their performances.

"We're pretty bullish on our prospects going forward here," Aetna Chief Financial Officer Joe Zubretsky said Thursday, after his company reported better-than-expected third quarter revenue and raised its 2011 earnings forecast.

Cigna said Friday its net income fell to $200 million, or 74 cents per share, in the three months that ended Sept. 30, from $307 million, or $1.13 per share, a year ago.

Adjusted income, which excludes the loss from one of its discontinued businesses, totaled $1.20 per share. Analysts surveyed by FactSet expected, on average, earnings of $1.23 per share.

Revenue climbed nearly 7 percent to $5.61 billion from $5.27 billion a year ago. Analysts expected $5.45 billion in revenue.

Company shares fell $1.07, or 2.3 percent, to $46.30 in morning trading Friday.

Cigna said Friday that its third-quarter results included losses totaling $179 million, or 66 cents per share, from its guaranteed minimum income benefits and variable annuity death benefits businesses due to low interest rates and volatile equity markets. That compares to losses totaling $44 million, or 16 cents per share, a year earlier.

Cigna discontinued those businesses in 2000 and operates them in run-off mode, meaning it seeks no new business. But they still hurt the company's performance when the market turns bad because Cigna's liabilities toward them increase.

Cigna is the fourth-largest commercial health insurer based on enrollment. It operates health care, group disability and life segments in the U.S. The insurer also has an international segment that sells individual insurance in several countries and operates an expatriate business that covers people living outside their home countries.

Premiums and fees from its largest segment, health care, slid 3 percent to $3.3 billion, and medical membership climbed slightly to about 11.5 million people.

The insurer has said its international business is an important source of future growth. Premiums and fees from that business grew 33 percent to $765 million in the quarter.

Cigna also said earlier this week it expects 2011 adjusted earnings of $5.05 to $5.30 per share, which is up from its previous forecast of $4.95 to $5.25. Analysts expect annual earnings of $5.29 per share.