LLY Pharmaceuticals · Mega cap · Obesity drugs · Incretins · Thesis updated June 10, 2026

Obesity engine with pricing and focus risk

Mounjaro and Zepbound now drive 65 percent of Lilly revenue, creating huge growth and heavy concentration.
Koundeo, Lilly’s new oral GLP 1 obesity drug, is off to a strong start, with about 80 percent of early users new to the class.
Management raised 2026 revenue guidance by $2 billion at the midpoint, even while expecting low to mid teens price headwinds.
The Medicare GLP 1 Bridge Program should expand obesity drug access starting July 1, 2026, but discounts must be offset by volume.
Kisunla, Verzenio, Taltz, Jardiance, and older diabetes drugs help diversify the company, but they are smaller than incretins today.
Key risks are manufacturing execution, payer pressure, counterfeit incretins, and the heavy bet on one treatment class.

01 Running thesis

A weight loss leader with one main engine

Lilly is now one of the main global suppliers of incretin medicines, a drug class used for type 2 diabetes and obesity. Mounjaro and Zepbound are the core products. In Q1 2026, they made up 65 percent of total company revenue. Total revenue for that quarter rose 56 percent to $19.8 billion. That is why Finn’s growth and performance view is strong.

The bull case improved after Q1 2026. Management raised full year 2026 revenue guidance by $2 billion at the midpoint, to a range of $82 billion to $85 billion. Early data for Koundeo, also called orforglipron, look positive. Lilly said just over 20,000 patients had been treated, and 80 percent of Koundeo prescriptions were new to the incretin class. That suggests the pill may bring in new obesity patients rather than only switch people away from shots.

Access is the other key point. Lilly said commercial access was confirmed with two large pharmacy benefit managers by mid May 2026, and Medicare access is set to start at the beginning of July through the Medicare GLP 1 Bridge Program. Strong international use of Mounjaro, even in markets with generic semaglutide, also supports the idea that Lilly’s dual agonist drug has a lasting edge.

The bear case is not gone. Lilly depends heavily on one drug family, and the stock already reflects a lot of expected growth. Management expects price to be a low to mid teens drag on growth in 2026, tied to government access deals, direct to patient pricing, and lower Medicaid prices for some older drugs. The next year will come down to Koundeo prescription trends, Medicare volume after July 1, manufacturing execution, and top line obesity data for retatrutide.

Jul 2026▲Initial Finn company page created after Q1 2026 results, highlighting that Mounjaro and Zepbound now make up 65 percent of revenue, Koundeo’s early launch is expanding the obesity market, and updated guidance raised 2026 revenue expectations by $2 billion while clarifying Medicare access and pricing trade offs.

Apr 2026▲Q1 2026 results reduced near term launch risk. Lilly raised full year revenue guidance to $82 billion to $85 billion, said Koundeo had 80 percent new to class early users, and confirmed commercial PBM access plus Medicare access starting July 1, 2026.

Feb 2026→The FY2025 10-K made the concentration risk clearer. Mounjaro and Zepbound were 56 percent of 2025 revenue, and Lilly disclosed voluntary U.S. government pricing agreements that shift the debate toward volume gains versus price cuts.

Feb 2026→Q4 2025 guidance showed very strong expected 2026 growth, but also a low to mid teens price headwind. That kept the core trade off in focus: more access and volume, but at lower realized prices.

Oct 2025▲Q3 2025 updates strengthened the pipeline case. Orforglipron obesity trials met key goals, Kisunla gained European Commission approval, and international Mounjaro demand looked strong.

02 Business model

Patents, scale, and access deals

Lilly discovers, tests, makes, and sells branded prescription drugs. It spends heavily on research and development, then runs clinical trials to prove a drug works and is safe. If regulators approve the drug, patents give Lilly a period with limited generic competition. That is when the company can earn back the cost of research and make a profit.

Most revenue comes through sales to wholesalers, pharmacies, and healthcare providers around the world. The model now depends most on cardiometabolic drugs. Mounjaro treats type 2 diabetes. Zepbound treats obesity. Koundeo is Lilly’s new oral GLP 1 for obesity. These drugs are driving volume growth, while lower realized prices are partly offsetting that growth.

Lilly also has other products that matter. Verzenio in cancer, Taltz in immunology, Jardiance in diabetes, Trulicity in diabetes, and Kisunla in Alzheimer’s disease help broaden the business. LillyDirect adds a direct to consumer path by connecting patients with telehealth providers and home delivery for some medicines. Lilly Employer Connect is a newer platform for employers to offer obesity medicines, but it is still early.

The model can break in a few clear ways. Lilly must keep building enough manufacturing capacity for incretins without quality problems or delays. It must also accept lower prices in some channels to reach more patients. The long term question is simple: can many more patients at lower prices create more profit than fewer patients at higher prices?

03 Product portfolio

The drugs that matter most

Growth engine

Mounjaro (tirzepatide, type 2 diabetes)

Mounjaro is Lilly’s leading diabetes incretin and a main driver of recent revenue growth. Together with Zepbound, it accounted for 65 percent of total revenue in Q1 2026.

Growth engine

Zepbound (tirzepatide, obesity)

Zepbound is the obesity brand of tirzepatide. It is a major growth driver, but access can change fast because large payers can favor rival drugs or demand lower prices.

Growth engine

Koundeo / Foundayo (orforglipron, oral GLP 1 for obesity)

Koundeo is Lilly’s oral GLP 1 obesity drug, approved by the U.S. FDA in April 2026. Early launch data showed 80 percent of prescriptions were new to the class, which supports the market expansion case.

Steady

Trulicity (dulaglutide, diabetes)

Trulicity is an older injectable GLP 1 for type 2 diabetes. It remains important, but it is later in its life cycle and faces pricing pressure as newer incretins take the lead.

Steady

Jardiance (empagliflozin, diabetes, partnered with Boehringer Ingelheim)

Jardiance is a diabetes drug sold with Boehringer Ingelheim. It adds steady cardiometabolic revenue, but it is not the main growth engine today.

Cash cow

Verzenio (abemaciclib, oncology)

Verzenio is a cancer drug used mainly in breast cancer. It helps diversify Lilly away from obesity and diabetes, even though it is smaller than the incretin franchise.

Steady

Taltz (ixekizumab, immunology)

Taltz treats immune conditions such as psoriasis and psoriatic arthritis. It provides recurring revenue and adds balance to the portfolio.

Option

Kisunla (donanemab, Alzheimer’s disease)

Kisunla is approved by the European Commission for early symptomatic Alzheimer’s disease. It gives Lilly a possible non obesity growth path, but adoption and reimbursement are still early.

04 Business segments

One segment, one big concentration

Mounjaro and Zepbound within human pharmaceuticals65%growing fast

Other human pharmaceutical products35%modest

Lilly reports one segment: human pharmaceutical products. For Q1 2026, Mounjaro and Zepbound made up 65 percent of total revenue, so the structured mix below separates that named concentration from the rest of the same reporting segment.

05 Risk factors

What could break the Lilly thesis

Too much reliance on incretins

High impact · Medium odds

Mounjaro and Zepbound accounted for 56 percent of Lilly’s revenue in 2025, then rose to 65 percent in Q1 2026. A safety issue, stronger competitor, or shift in doctor use for incretin drugs would hit most of Lilly’s growth at once. Koundeo lowers some risk if it expands the market, but it also keeps Lilly tied to the same broad drug class.

We watchTrack the share of total revenue from Mounjaro, Zepbound, and Koundeo in each filing, plus any label changes or safety updates for incretin drugs.

Manufacturing falls behind demand

High impact · Medium odds

Lilly is carrying out large manufacturing expansion plans to meet demand for obesity and diabetes drugs. The company says tirzepatide supply currently exceeds U.S. demand, but demand can change fast. Any delay, quality issue, or capacity shortfall could lead to shortages, lost sales, or regulatory problems tied to manufacturing standards.

We watchWatch management comments on supply, capacity, shortages, product allocation, and manufacturing quality in earnings calls and MD&A.

Payers take more price

High impact · High odds

Lilly has voluntary agreements with the U.S. government to lower Medicaid and some other drug prices. Management expects price to be a low to mid teens drag on growth in 2026. CVS Caremark also stopped covering Zepbound as a preferred obesity drug on some plans in July 2025, showing how private payers can limit access.

We watchTrack realized price trends, PBM formulary changes for Zepbound and Koundeo, and volume under the Medicare GLP 1 Bridge Program.

Koundeo fails to expand the market

High impact · Medium odds

Early Koundeo data showed 80 percent of users were new to the incretin class. That is good for the bull case, because it means new patients may be entering treatment. If that mix shifts and Koundeo mostly takes patients from Mounjaro or Zepbound, the financial benefit would be weaker.

We watchMonitor Koundeo prescription trends, new to class patient mix, refill rates, and any comments on cannibalization after the Q3 2026 direct to consumer ad launch.

Competition and counterfeit incretins

Medium impact · Medium odds

Diabetes, obesity, and oncology are competitive markets. Rivals are developing injectable and oral obesity drugs that could lower Lilly’s share or force lower prices. Lilly also warns about counterfeit, misbranded, adulterated, and compounded incretins, which can confuse patients and harm trust in the category.

We watchFollow competitor trial results, obesity drug approvals, payer coverage choices, and Lilly’s risk factor updates on counterfeit or compounded incretins.

Patent or regulatory setbacks

Medium impact · Medium odds

Lilly’s profit depends on patents and regulatory approvals. If patent protection weakens, generic or biosimilar competition could arrive sooner than expected. Regulatory setbacks can also delay new uses for existing drugs, as seen when Lilly withdrew its U.S. filing for tirzepatide in heart failure after the FDA asked for another confirmatory trial.

We watchMonitor patent litigation, patent expiry timelines, FDA and EMA decisions, and any new required safety or confirmatory studies.

06 Quick answers

In one breath

How does Eli Lilly make most of its money today?

Lilly makes most of its revenue from patented prescription drugs. Today the biggest drivers are Mounjaro and Zepbound, which treat type 2 diabetes and obesity and made up 65 percent of Q1 2026 revenue.

What is Koundeo and why does it matter?

Koundeo, also called orforglipron or Foundayo, is Lilly’s oral GLP 1 drug for obesity. It matters because early launch data showed 80 percent of prescriptions were new to the incretin class, which suggests it may expand the obesity market.

Why is pricing such a big issue for Lilly?

Lilly is gaining access to larger patient groups, including through government programs, but often at lower prices. Management expects price to be a low to mid teens drag on growth in 2026, so volume has to make up the difference.

Is Eli Lilly’s stock price already assuming success?

Finn’s valuation view is only mid range, while growth and performance score much higher. That means the business is strong, but the market already expects a lot from obesity drugs, Koundeo, Medicare access, and future pipeline wins.