In the wave of Monday morning's earning reports Aetna topped the Street's forecast, but missed on its 2016 projected earnings.
The health insurance giant earned an adjusted $1.37 per share in its latest quarter, beating estimates by 16 cents, and its revenue also topped forecasts. Aetna was helped by improved membership numbers and margins in its Medicare business. The company expects 2016 earnings of $7.75 per share, below estimates for $8.05 a share.
"I think Street consensus was built from a number of other aspects. Our stock is up today; our number was at least $7.75 a share, which is 10 percent of the baseline for '15," Aetna CEO Mark Bertolini said Monday on CNBC's "Closing Bell."
"We think our guidance is appropriately prudent at this time given all the changes that will happen in '16 around the Affordable Care Act and the changes in taxes and fees in the Affordable Care Act," Bertolini said.
Aetna shares rose 1.5 percent Monday.
Bertolini announced that the company is in the last stages to acquire health insurance company Humana. He said the union may not result in layoffs for Kentucky-based Humana.
"We have made a commitment to the Louisville marketplace that that will be our government headquarters," he said. "We see that organization growing, actually."
Aetna forecasts the acquisition will push earnings per share to $11 by 2018.
"When we get done with this transaction, we'll be able to address markets that comprise 91 percent of the seniors across the United States for Medicare, which will give them a real opportunity to have a national product," he said. "More importantly, it will allow us to invest in moving care closer to home, getting higher-quality care at home."
— CNBC's Peter Schacknow contributed to this article.