After Optum bought ambulatory surgical centers, prices went up

Surgeries are moving outpatient, and ambulatory surgical centers (ASC) are getting a reputation for being a great value.

These centers have caught the eye of payers because they generally charge lower prices than hospitals for the same surgery—and they’ve caught the attention of investors with their fast-growing revenue, up to $54.3 billion in 2026, per research firm IBISWorld.

But after being bought by UnitedHealth Group’s health services subsidiary, Optum, these surgery centers’ prices rose an average of 11%, a February study found.

The study, published in Health Affairs, looked at commercial claims from 2015 to 2018 for seven sampled procedures across 24 of Optum’s centers.

The claims data didn’t include the prices charged to UnitedHealthcare, but it found that prices charged to other private insurers rose 11%, an average of $239 per procedure, increasing spending by about $10.1 million a year. This was driven by an increase in professional fees, according to the study. Extrapolating from those seven procedures to all procedures, the authors estimate that’s more than $67 million per year.

This finding “aligns with concerns that vertical integration enhances bargaining leverage,” the study authors wrote. “These costs are likely passed on to consumers through higher premiums and increased out-of-pocket spending in the form of deductibles and coinsurance,” the study read.

In a statement to Healthcare Brew, Optum’s SCA Health spokesperson Olivia Serdy criticized the study’s use of “outdated, unrepresentative data” and said it “does not adequately account for regulatory requirements that affect referral behavior and pricing.”

A bigger trend. United is one of several healthcare companies that have become payviders over the last few years, including Aetna’s parent company CVS, which bought Oak Street Health in 2023, and Elevance Health, whose Carelon healthcare services division acquired home health provider CareBridge in 2024.

UnitedHealth Group’s Optum entered the ASC market in 2017 when it paid about $2.3 billion for Surgical Care Affiliates, a surgery chain with 205 surgical facilities at the time of acquisition, and rebranded it as SCA Health.

It’s a “relatively uncommon” but “growing trend” for payers to buy up ASCs, Yashaswini Singh, a healthcare economist and assistant professor at Brown University’s School of Public Health, told us over email.

As more surgeries move to ASCs, payviders that invest in these facilities get the best of both worlds. When their patients go to an ASC instead of a hospital, payers spend less on the insurance side compared to when patients go to a hospital, according to TK. And if that payer’s enrollees (or other payers’ enrollees) happen to go to an ASC that they own, they also profit on the provider side.

“Optum has been particularly aggressive in this space,” Singh said.

What about private equity? It’s more common for facilities like ASCs to be bought by hospitals or private equity (PE) than by payers, Singh added.

PE funds have targeted ASCs in recent years as surgeries shift to these locations, per an October 2025 report by nonprofit watchdog the Private Equity Stakeholder Project (PESP).

Generally, PE firms will sell off acquired practices to other PE firms, April 2024 research coauthored by Singh found, though it didn’t focus on ASCs specifically. But there have been a few big exceptions. After Kelso Private Equity bought gastroenterology practice Capital Digestive Care, for example, Optum’s SCA Health acquired it in 2022. SCA acquired another large gastroenterology physician group from a PE firm in January 2025.

The PESP report also pointed to nonprofit healthcare chain Ascension, which began the acquisition process for ambulatory surgery company AmSurg last year from PE group Pacific Investment Management, with plans to finalize in Q1 2026.

“Essentially, we’re seeing a PE-to-payer pipeline where private equity restructures practices then flips them to consolidators. This two-stage consolidation likely has compounding effects we don’t fully understand yet,” Singh said.

Wait, there’s more! Research that previously looked at how UnitedHealth’s acquisition of physician practices affected prices found no significant effect for most practices. The February study is the first study to investigate the impact of United’s ASC acquisitions on market dynamics specifically.

The study also investigated whether Optum-owned physician practices were more likely to steer patients toward ASCs over hospitals, particularly Optum-owned facilities.

The theory here was a payvider might tell its doctors to send more patients to its integrated ASCs because it would benefit on multiple levels: lower cost for its payer arm and more business for the surgical centers it owns.

UnitedHealth Group has been accused of pressuring its physicians to change how they practice medicine in the past, but again, there was no published research into acquisitions of ASCs before this month.

The researchers didn’t find a significant relationship one way or the other between Optum-owned and non-Optum-owned physician practice referrals, but it did find Optum was more likely to purchase a physician practice that was already directing more patients to ambulatory centers over hospital-owned outpatient departments, something the authors called “strategic selection.”

“Although our findings on referral patterns are consistent with strategic selection rather than postacquisition steering, this consolidation of efficient providers under a single entity raises long-term questions about patient choice and local market dynamics,” the study reads.