MedPAC's March 2026 Report Exposes Cracks in Medicare Part D Sustainability

The Medicare Payment Advisory Commission (MedPAC) released its March 2026 report to Congress, painting a stark picture of accelerating costs in the Medicare Part D program. Medicare spending per beneficiary grew faster for Part B than Parts A and D in recent years, but Part D trends are now alarming: total program spending surged nearly 18% between 2023 and 2024, propelled by rising drug costs and utilization.[1] High-cost brand-name drugs and biologics without generic competition account for 83% of gross Part D spending, despite comprising just 10% of prescriptions.[1] This imbalance is intensifying pressures on insurers, pharmacies, and policymakers, with ripple effects across healthcare equities.

Part D Bids and Costs Skyrocket into 2026

Plan bids and expected costs have escalated dramatically. The national average monthly bid amount (NAMBA) rose nearly 180% in 2025 and an additional 33% in 2026.[1] Total expected basic benefit costs jumped 35% in 2026, reflecting higher anticipated drug spending and utilization.[1] Milliman's MedIntel analysis corroborates this, showing total Part D gross cost per member per month (PMPM) increased 33% for non-low-income (NLI) members and 10% for low-income (LI) members between 2024 and 2025.[2]

These trends diverged sharply post-2024, when the first true maximum out-of-pocket (OOP) limit for NLI members spurred spending spikes, especially in specialty drugs.[2] NLI specialty PMPM more than doubled from $84 in Q4 2023 to $190 in Q4 2025—a 127% rise over two years.[2] Quarterly growth moderated to 7.1% in Q4 2025 from double-digits earlier, but remains elevated versus prior-year levels.[2]

GLP-1 receptor agonists, like those from Eli Lilly and Novo Nordisk, emerged as the largest cost driver. Combined GLP-1 PMPM across individual Part D markets hit $66.13 in Q4 2025, up 92% from $34.48 in Q1 2024.[2] This class alone underscores how demand for obesity and diabetes treatments is reshaping Part D economics, benefiting pharma innovators while straining payers.

Implications for Insurance Providers and Healthcare Stocks

Medicare Advantage Prescription Drug (MA-PD) plans remain robust, but standalone Prescription Drug Plans (PDPs) face existential threats. PDP offerings declined 22% between 2025 and 2026, with steeper drops in enhanced plans.[1] Diverging costs, premiums, and risk scores between PDPs and MA-PDs raise viability concerns, potentially consolidating market share toward integrated giants like UnitedHealth Group (UNH), Humana (HUM), and CVS Health (CVS).

Premium stabilization policies, including a 6% cap on base beneficiary premium growth and the Part D Premium Stabilization Demonstration, have kept average premiums in check but widened variation across plans.[1] Medicare's share of program financing climbed to 86.8% in 2026, shifting liability from beneficiaries and plans to federal coffers.[1] This dynamic supports near-term stock stability for MA-PD leaders but signals long-term fiscal risks if spending growth persists.

UnitedHealth, with its OptumRx pharmacy benefits manager (PBM), reported robust Q4 2025 results partly buoyed by Part D scale, but analysts flag bid pressures as a 2026 headwind. Humana, heavily exposed to Medicare Advantage, saw shares dip 3% post-report on PDP erosion fears. CVS/Aetna, leveraging integrated care, may gain from MA-PD resilience, with Aetna's Part D enrollment steady amid bid hikes.

Risk adjustment misalignments persist: Part D scores overpredict MA-PD costs and underpredict PDPs, despite CMS's 2025 normalization factors.[1] Further tweaks could recalibrate payments, favoring efficient operators and pressuring underperformers—bullish for data-savvy incumbents.

Digital Health Companies: Opportunities Amid Cost Pressures

Digital health firms stand to benefit as payers seek utilization management tools. The elimination of beneficiary cost-sharing above the OOP threshold reduces barriers to high-cost drugs but hampers plans' utilization controls.[1] Platforms offering AI-driven prior authorizations, adherence monitoring, and telehealth for chronic care—like Teladoc Health (TDOC) or Hims & Hers (HIMS)—could see uptake. GLP-1 demand, now spilling into cash-pay markets, amplifies this: Lilly's out-of-pocket strategies highlight a pivot where digital prescribers thrive.[5]

Investors note Teladoc's chronic care segment grew 15% YoY in Q4 2025, positioning it to capture Part D-driven volume. Smaller players in value-based care analytics may consolidate, echoing M&A trends favoring scale against rising compliance costs.

Pharma Winners and Policy Wildcards

High-cost specialties dominate: immunology and oncology accelerated in 2025, alongside GLP-1s.[2] Eli Lilly, betting on sustained leadership in incretins, structured pricing for out-of-pocket growth, insulating revenues from Part D volatility.[5] Merck's ARPA maneuvers and Cigna's 340B strategies illustrate adaptive plays, but net effects of Inflation Reduction Act (IRA) provisions—like Drug Price Negotiation and inflation rebates—remain uncertain, potentially curbing manufacturer rebates and inflating plan bids.[1]

Public sentiment amplifies urgency: 59% of adults worry about affording prescriptions in 2026, up steadily since 2018, with 43% skipping doses due to cost.[4] Bipartisan support exceeds two-thirds for more regulation, including IRA measures.[4] Trump's second-term initiatives, like TrumpRx coupons launched early 2026, have low visibility but tap popular international referencing ideas.[4] Under his proposal, cash prescriptions would count toward deductibles, potentially boosting adherence and costs further.[6]

Pharma stocks like LLY gained 2% post-Pharma 50 rankings, reflecting GLP-1 dominance, while broader sector faces headwinds from procurement leaders citing rising costs as 2026's top challenge.[8]

Marketplace Premiums Add to Affordability Squeeze

Beyond Part D, CMS data shows Marketplace out-of-pocket premiums rose $65 monthly in 2026 to $178, post-enhanced tax credit expiration.[3] This compounds Part D trends, pressuring commercial insurers like Elevance Health (ELV) and Centene (CNC), with Medicaid-heavy players vulnerable to spillover utilization.

Investment Outlook: Selective Bullishness in Turbulent Waters

Healthcare stocks face bifurcated prospects. Insurers with PBM scale—UNH, CVS—offer defensive appeal, potentially rerating higher on MA-PD strength. Digital health disruptors gain traction in cost containment, meriting overweight allocations. Pharma selects like LLY shine on innovation premiums, but watch IRA negotiations.

Part D spending growth, if unchecked, risks policy overhauls, yet current trajectories favor incumbents adapting fastest. With NAMBA up 33% and specialty costs doubling, 2026 bids signal a sector ripe for M&A and efficiency gains. Bullish investors target integrated models, eyeing 8-12% upside for top-tier names amid volatility.

Stakeholders must monitor Q1 2026 enrollment data and CMS risk refinements, as PDP fragility could accelerate MA-PD dominance, reshaping competitive landscapes profitably for survivors.