(Bloomberg) -- Aetna Inc.’s agreement to buy Humana Inc. for$37 billion is another link in a chain of U.S. health insuranceacquisitions spurred by Obamacare.

The purchase, announced Friday, comes on the heels ofyesterday’s announcement by smaller insurer Centene Corp. that it will buy Health Net Inc.for about $6.3 billion.

Read: Centene to buy Health Net in $6.3 billion health-caredeal

Obamacare, or the Patient Protection and Affordable Care Act,created millions of new customers for insurance coverage andencourages insurers to look for savings. Aetna’s deal means it willgain more than 14 million Humana customers in commercial, Medicareand Medicaid plans. By purchasing Health Net, Centene creates thebiggest private administrator of Medicaid, a federal program forthe poor.

Here are other combinations that may be in the works:

*Anthem Inc. may try again for Cigna Corp. The target rejected a$47 billion takeover bid last month. Cigna said the offer wasn’t inthe best interest of shareholders and that Anthem executives aren’tfit to lead a merged giant.

*UnitedHealth Group Inc. -- the biggest of the U.S. healthinsurers -- may try to grab Aetna. Before Aetna announced theHumana purchase, Barclays Plc analyst Joshua Raskin said aUnitedHealth-Aetna combo makes the most sense because of costsavings and the scale it would produce.

*Anthem had weighed a bid for Humana, according to a personfamiliar with the matter, and could try to outbid Aetna.

*Cigna may try to play the wolf rather than the sheep. Bloombergreported on June 25 that the company had made an offer for Humana,but that Humana’s board was said to prefer Aetna’s bid.

*UnitedHealth could jump in with a competing offer for HealthNet, said Ana Gupte, an analyst at Leerink Partners LLC.

*Further deals among smaller companies may occur. Centene andHealth Net’s combination suggests that firms that aren’t among thefive biggest will be taken in by the Obamacare-fueled mergerfrenzy.

--With assistance from Phil Serafino in Paris and Zachary Tracerin New York.

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