Profit continued to pile up at Minnetonka-based UnitedHealth Group during the third quarter, the health insurance giant said Tuesday, as company executives didn't sound worried about a rumored entrance by retail giant Amazon in the pharmacy business.

UnitedHealth Group shares advanced 5.5 percent Tuesday after the company said earnings jumped 26 percent for the third quarter, beating analyst estimates and prompting a boost to full-year financial guidance.

The quarterly results were the first reported under new CEO David Wichmann, who took over the top job in September from longtime Chief Executive Stephen Hemsley.

"We will continue to engage with innovative and thought-leading organizations and seek to serve consumers better managing their health care needs in helping make health systems work better for everyone," Wichmann said during a conference call with investors when asked about the Amazon rumors.

Earlier this month, analysts with Leerink published reports saying an arrival by Seattle-based Amazon in some aspect of the pharmacy business is likely within the next two years. They wrote that the move would be most threatening to retail pharmacy companies, while adding that UnitedHealth Group's growing pharmaceutical benefit management (PBM) business would be "most buffered" among the nation's big three PBMs.

The Leerink analysts added that Eagan-based Prime Therapeutics might have had talks with Amazon, and would be "interested in a partnership ... given it is aspiring to Big 3 status." A spokeswoman for Prime Therapeutics, which manages pharmacy benefits for several Blue Cross insurers, declined to comment.

The PBM business is part of UnitedHealth Group's fast-growing Optum division for health services, which also includes non-hospital health care providers and technology services. Wichmann said UnitedHealth Group would continue to focus investments going forward on the Optum division.

"The more significant investments that we'll make going forward, particularly on the growth front, will be through Optum, as we have in the past," he said.

Health plans hire PBMs to manage medication benefits for enrollees, including negotiations on the cost of drugs and the creation of pharmacy networks.

In their report on Amazon, the Leerink analysts said that Optum was the third largest PBM in terms of total prescription claims, with 22 percent of the market in 2015 behind St. Louis-based Express Scripts and Rhode Island-based CVS Caremark. Prime Therapeutics ranked No. 5, they wrote, with an 8 percent share of the market.

The Optum PBM would be buffered against an Amazon entry, the Leerink analysts wrote, because it doesn't own retail pharmacies and trades on connections to large health insurers.

During Tuesday's conference call, John Prince, the chief executive of the OptumRx business, said of Amazon that his company is "channel agnostic" in terms of where people want to pick up prescriptions.

"We are open to new distribution partners," Prince said. "We have deep relationships with CVS, with Walgreens and with other partners in the market."

For the third quarter, UnitedHealth Group reported earnings of $2.49 billion on $50.32 billion in revenue, compared with earnings of $1.97 billion on $46.29 billion in revenue during the year-ago quarter.

After adjusting for one-time factors, its $2.66 earnings per share easily topped the $2.56 per share expected by analysts surveyed by Thomson Reuters.

UnitedHealth Group now expects adjusted net earnings for the year of about $10 per share, up from a previous range of $9.75 to $9.90.

At the end of the third quarter, nearly 45 million people in the U.S. were covered by UnitedHealthcare health insurance, up about 845,000 people, or 2 percent, from the same quarter last year. Much of the growth came from the sale of Medicare Advantage plans to seniors, as well as supplemental Medicare policies.

During the third quarter, earnings from operations grew at a slightly higher rate at Optum than in the health insurance business, although both posted double-digit growth.

Going forward, UnitedHealth Group will make "selective" investments globally, Wichmann said. He added that the company will continue making small "plug-in" acquisitions in the health insurance business.

In Brazil, UnitedHealth Group sells health insurance while also operating hospitals and clinics. Last month, regulators in Chile disclosed the company is in the process of acquiring a health plan in the country that also operates in Colombia and Peru.

UnitedHealth Group employs about 18,000 people in Minnesota. This month, the company's UnitedHealthcare division — which is the nation's largest health insurer — announced expansions into the commercial markets in Maine and Minnesota.

UnitedHealth Group shares closed Tuesday at $203.89, up more than 5.5 percent for the day.

Twitter: @chrissnowbeck