Despite UnitedHealth (UNH) - Get Report reporting better-than-expected earnings on Tuesday, the company's share price fell 1.6%.

The company reported earnings of $2.11 per share for the fourth quarter of 2016, 4 cents more than street consensus estimates of $2.07 per share. The company's total revenue rose 9% to $47.52 billion, compared with consensus estimates of $47.26 billion.

Despite positive earnings, UnitedHealth saw shares fall by approximately $2.40 per share, hitting $159.42 after the market open on Tuesday.

This is likely due to uncertainty surrounding the Affordable Care Act, particularly following remarks President-elect Donald Trump made to the Washington Post over the weekend.

The incoming Trump administration has said it would aggressively repeal Obamacare, but Republicans have yet to design a health care plan to replace it. Trump indicated Saturday that he wants a plan giving everyone access to health coverage, but he, like the newly minted Congress, has not offered more than the outlines of a replacement plan.

UnitedHealth has largely pulled out of the public exchanges set up by the Affordable Care Act. However, other benefits implemented through the Affordable Care Act, like mandated health insurance, could go away once the act is repealed.

On Tuesday, the Congressional Budget Office released a report that showed in the first year of Obamacare repeal, 18 million Americans could lose their coverage. Eventually, that number could balloon to 32 million. Those numbers, however, do not take into account whatever steps Republicans may take to replace Obamacare.

Perhaps more challenging for companies like Unitedhealth, the CBO expects premiums to skyrocket between 20 and 25% higher than where they currently sit. 

"We do not believe our ACA-compliant individual business carries any financial exposure forward into 2017," said David Wichmann, president of UnitedHealth, during the company's investor call Tuesday.

Evercore analyst Michael Newshel noted that UnitedHealthcare is well-insulated from any downside that could come from repealing the Affordable Care Act. Jefferies analyst David Windley agreed, noting also that these issues will likely impact UnitedHealth in the long term. Both rate the stock a buy.

UnitedHealth's Optum seemed to particularly drive growth during the fourth quarter. The division's revenues grew 24% to $83.6 billion, while earnings from operations grew 32% to more than $5.6 billion.

Though analysts expected the company to provide more information on its acquisition of Surgical Care Affiliates (SCAI) . It revealed the deal on Jan. 9 amid a bevy of health care deals announced at the J.P. Morgan Healthcare Conference.

The deal, which valued Surgical Care at $57 per share, is worth $2.3 billion in total. Optum Rx was the acquisition vehicle used by UnitedHealth. The deal is expected to close in the first half of 2017. UnitedHealth will pay for 51% to 80% of the acquisition in stock and fund the rest of the deal in cash.

Investors and analysts on the call did not focus on the deal, though.