The current market leaders could run into some challengers.
Major health insurers should detail results that stack up well to expectations when they begin reporting on the fourth quarter, but investors will be focused more on how the new year is shaping up, according to analysts who cover the sector.
UnitedHealth Group Inc., the nation's largest insurer, kicks off earnings reports for managed care companies when it releases results Thursday morning.
Big insurers should at least meet, if not beat, expectations in the quarter, Bernstein analyst Ana Gupte said in a research note. The analyst said concerns about a broad increase in health care use in the fourth quarter, due in part to a recovering economy, appear to be overblown.
Investors and analysts also have worried about a flu season that is shaping up to be more intense than during recent seasons. That can hurt insurers if they receive more claims for care than they expected.
Barclays analyst Josh Raskin said in a separate note that concerns about the flu also are overstated. He noted that cases may not have spiked until late last month, and it may have a bigger impact on the first quarter. He also said insurers set aside reserves to cover flu claims, and the illness tends to result in the use of low-cost health services.
Raskin said fourth-quarter results are relatively unimportant to investors, and he expects a greater focus on expectations for the new year.
After UnitedHealth, WellPoint Inc., the nation's second-largest insurer, reports earnings Jan. 23. Aetna Inc. follows on Jan. 31, Humana Inc. reports its results Feb. 4, and Cigna Corp. releases results Feb. 7.
The sector had a choppy 2012 with shares from only one of the five largest health insurers exceeding the Standard & Poor's 500 index advance of more than 13 percent. Cigna climbed 27 percent to close 2012 at $53.46, Aetna was up 10 percent to $46.31, and UnitedHealth rose 7 percent to $54.24.
Meanwhile, Humana shares sank 22 percent to $68.63, and WellPoint's stock dropped 8 percent to $60.92.
In morning trading Wednesday, all the stocks were down roughly 1 percent, in line with the broader market.