Do you believe that "small ball" wins the World Series or do you fall in with the camp that says "chicks dig the long ball"? If you're a fan of swinging for the fences, Humana (NYSE:HUM) might be a health plan company more up your power alley. While I've previously expressed nervousness with the company's aggressive underwriting philosophy, that strategy now appears to be paying off.

Humana reported robust financial results, since the company has been absorbing a much greater amount of Medicare business. As the ranks of its prescription drug plan membership swelled, revenue was up more than 52%, and overall medical membership rose 57%. Here's something to keep in mind, though -- while it's true that the company beat estimates, operating income was up 16%, net income was up 10%, and the margins in prescription drug business were on the low end of guidance. That doesn't exactly vanquish the worries that Humana bit off more than it may be able to chew.

With the huge influx of new members, I'm not sure what to make of the medical expense trends. The medical loss ratio was up both annually and sequentially, and up is bad. But the business is different now, so it will take a little longer to get a sense of how Humana is executing on cost control.

UnitedHealth (NYSE:UNH), WellPoint (NYSE:WLP), and Aetna (NYSE:AET) all have Medicare businesses and prescription drug plans, but not to the same degree as Humana. And that's the good news/bad news for Humana -- if they bid this Medicare business right, they'll see growth in a time when other health insurers are fighting to grow membership rolls and control medical expenses (to preserve the profit growth to which investors have become accustomed). If they bid wrong ... well, it won't work out so well.

A few years from now, I'm betting people will look back and either applaud the company's aggressive foresight or mock its pretensions and mistakes. Since I really don't know which way it's going to go and don't have much confidence in the stock, I won't be buying these shares for myself.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).