Overview of the Dispute
Nearly a month after Mount Sinai Health System went fully out of network with Anthem Blue Cross Blue Shield, the two healthcare giants remain deadlocked. Billing practices and contract protections sit at the center of the standoff. While both sides say they agree on rate increases, they disagree sharply on terms that govern how claims are reviewed and paid. As a result, roughly 200,000 Anthem members who receive care from a Mount Sinai provider each year now face higher out-of-pocket costs or must switch providers.
This dispute reflects a growing national trend. Insurers and hospital systems are clashing more publicly — and more bitterly — over contracts. For New Yorkers, the fallout is immediate and personal.
How the Network Split Unfolded
A Contract That Expired Without a Resolution
Negotiations between Mount Sinai and Anthem began in spring 2025. The contract expired December 31, 2025, which caused 9,000 physicians to exit Anthem’s network immediately. Hospitals and facilities followed later.
On January 1, 2026, New Yorkers enrolled in Anthem Blue Cross Blue Shield health plans received news that their insurer had broken up with Mount Sinai. Coverage for the health system’s hospitals, outpatient centers, and other facilities ended on March 4, 2026.
Medicare Advantage Members Hit First
Despite Anthem’s efforts to keep Mount Sinai doctors and hospitals in its network, Mount Sinai executives refused offers to do so. As a result, Mount Sinai physicians, specialists, and allied healthcare professionals exited Anthem’s Medicare Advantage network on January 1, 2026, with hospitals following on March 4.
What Each Side Is Arguing
Anthem’s Position: Protecting Patients From Billing Errors
Anthem insists it agreed to reasonable price increases. However, it draws the line at what it calls billing safeguards. Anthem argues that Mount Sinai executives are asking to bill patients as they wish without checks to prevent erroneous charges, and that the insurer cannot agree to changes that would severely undercut accountability, transparency, and billing accuracy.
Anthem’s spokesperson stated that the two sides had reached agreement on rates and all other negotiating terms, with a contract ready to sign — but at the last minute, Mount Sinai refused to move forward unless Anthem agreed to eliminate basic consumer protections.
Mount Sinai’s Position: Anthem Blocks Patient Protections
Mount Sinai tells a very different story. The health system says Anthem stepped away from finalizing an agreement that was within reach, and that Mount Sinai made repeated good-faith efforts over several months to restore in-network access for patients.
According to Mount Sinai, the dispute goes beyond reimbursement rates. The health system states these negotiations involve Anthem’s chronic denials of medically necessary care, delayed payments, and administrative practices that create barriers for patients and physicians alike.
Furthermore, Mount Sinai reports that Anthem reimburses it up to 35 percent less than other major New York health systems for comparable services, and that the insurer is seeking single-digit annual increases over three years — not the steep 50 percent hike Anthem publicly claimed.
The $450 Million Payment Gap
Outstanding Claims Deepen the Standoff
Money already owed adds another layer to this conflict. Anthem currently owes Mount Sinai hundreds of millions of dollars for care already delivered to its members — care that was provided, claims that were submitted, and payments that remain outstanding.
Mount Sinai reports that Anthem owes it more than $450 million for previously delivered care. The health system frames this not as a billing dispute but as a straightforward debt. Mount Sinai argues that Anthem is effectively using it as an interest-free bank while the insurer reports record profits.
This unpaid balance makes compromise harder. Mount Sinai cannot afford to sign a new contract without resolving what it says it is already owed.
Impact on Patients
Patients Caught in the Crossfire
As both sides trade accusations, everyday patients bear the cost. Patients in an ongoing course of treatment at Mount Sinai — for serious illnesses, pregnancy care, or other conditions — can remain with their physicians under Anthem’s continuity-of-care provisions. Other patients must reschedule care with a different in-network provider, or risk paying out-of-network bills.
Because Anthem no longer considers Mount Sinai in network, Anthem determines what portion of care it will cover and what portion the patient may be required to pay out of pocket — which could be significantly higher than in-network rates.
This Is Not the First Time
This situation is not unprecedented. Tens of thousands of patients on UnitedHealthcare and Oxford health plans were forced out of network in 2024 due to a dispute between those insurers and Mount Sinai. The pattern raises serious questions about long-term network stability in New York.
What Anthem Members Should Do Now
Practical Steps to Protect Your Care
If you hold Anthem coverage and receive care at Mount Sinai, act quickly. Here is what experts and both organizations recommend:
- Check your continuity-of-care eligibility. Patients receiving ongoing treatment for serious conditions, mental health disorders, or terminal illness may qualify to stay at Mount Sinai under Anthem’s extended provisions.
- Call Anthem directly. Use the number on the back of your insurance card to ask about out-of-network costs and continuity-of-care options.
- Talk to your HR department. If you receive Anthem insurance through your employer, ask your HR or benefits department to advocate with Anthem on your behalf.
- Review your out-of-network benefits. Know what your plan covers before scheduling any non-emergency procedures.
- Emergency care remains protected. By law, insurance companies must cover emergency services at in-network rates, regardless of network status.
The Bigger Picture for U.S. Healthcare
A Sign of Things to Come
This standoff is not simply a New York story. Contract squabbles between payers and providers are nothing new, but disputes are increasingly creeping into the public eye as insurers try to keep a lid on rising medical costs and providers seek generous rate updates, citing inflation and higher costs of doing business.
Providers are also pushing back against administrative provisions like prior authorization requirements, which allow payers to delay care under the guise of medical necessity reviews. The dispute reflects broader pressures on payers and providers, with rising costs and administrative inefficiencies driving contentious contract battles and highlighting the need for deeper cost-control innovation.
Elevance Health, Anthem’s parent company, is the second largest for-profit insurer in the country, with more than $197.6 billion in revenue and more than $5.7 billion in profit in 2025. Critics argue that these profit levels make it harder for health systems to justify below-market reimbursements.
Until both sides commit to enforceable terms, New York patients remain caught in the middle — uncertain about their coverage, their costs, and their care.
