On February 4, 2026, two companies reported earnings on the same day. One guided revenue 7% above consensus. The other warned of its first sales decline in a quarter century. Both sell GLP-1 drugs. Both dominate the obesity market. The numbers told completely different stories.
What Happened
Both companies sell GLP-1 receptor agonists — the drug class that's reshaping obesity treatment and generating the fastest revenue ramp in pharmaceutical history. But their Q4 2025 earnings told opposite stories about where this market is headed.
Eli Lilly posted Q4 revenue of $19.3 billion, up 43% year-over-year. Mounjaro and Zepbound (both tirzepatide-based) more than doubled, now accounting for over 60% of quarterly sales. Full-year 2025: 45% revenue growth, 96% EPS growth. Then Lilly guided 2026 revenue to $80–83 billion — $2.4 to $5.4 billion above where analysts expected.
Novo Nordisk warned of a potential 13% sales decline at constant exchange rates — the company's first revenue drop in 25 years. Shares cratered 18% at the Copenhagen open, erasing roughly $50 billion in market cap. Two top executives headed for the door.
The Three Forces Splitting This Market
Trump's Most Favored Nation policy and direct-to-consumer pricing have created low- to mid-teens percentage pricing headwinds globally. Lilly's CEO Ricks acknowledged "a step down in pricing" but said volume growth "will ramp on the back half." Novo faces the same headwinds plus patent expiries on semaglutide in Brazil, Canada, and China — and it doesn't have the volume trajectory to absorb the hit.
Lilly's share of the U.S. obesity and diabetes drug market hit 60.5% in Q4 — up 2.6 percentage points from Q3. This happened before Novo's Wegovy pill launched in January 2026. Tirzepatide's dual GIP/GLP-1 mechanism appears to be winning the prescribing war against semaglutide's GLP-1-only approach.
Lilly's pipeline reads like a GLP-1 expansion playbook: orforglipron (oral GLP-1 for obesity, expected Q2 2026 launch), retatrutide (triple agonist for obesity + osteoarthritis), and Taltz + Zepbound combination for psoriatic arthritis with obesity. Meanwhile, Medicare coverage opening in 2026 gives Lilly access to 40 million new beneficiaries — CEO Ricks called this "quite expansive to volume."
The Buried Signal
Novo's Wegovy pill attracted 170,000 patients in its first four weeks. That's a strong launch. But it wasn't enough to change the guidance math. When your oral formulation launches strong and you still guide for a sales decline, the problem isn't demand — it's that your competitor is taking the market faster than your new products can recapture it.
This is the signal the headlines missed. Novo isn't failing because obesity drugs are failing. Novo is failing because tirzepatide is winning — and the pricing environment rewards whoever has the volume momentum to absorb the hit.
The Broader Q1 Context
This divergence is playing out against a Q1 2026 earnings season that looks broadly healthy:
| Metric | Current | vs. Start of Q1 |
|---|---|---|
| S&P 500 EPS Growth Est. | +13.0% | +0.2pp |
| Bottom-up EPS Est. | $71.24 | −0.5% |
| Positive Guidance Issuers | 60 | vs. 44 avg |
| Negative Guidance Issuers | 50 | — |
| Top Sector: Info Tech | +45% | +10pp |
| CY 2026 EPS Est. | $313.62 | +0.8% |
The Q1 bottom-up EPS estimate fell just 0.5% since December 31 — far better than the 5-year average decline of 1.6% and the 10-year average of 2.9%. More companies are guiding positively (60) than negatively (50), with positive issuances well above the 5-year average of 44. But strip out Tech's outsized +45% growth contribution, and the rest of the S&P 500 is growing at just +5%.
What to Watch
For Lilly: The Q2 oral GLP-1 (orforglipron) launch will be the next catalyst. If the pill form expands the addressable market beyond injectable-willing patients, Lilly's volume story accelerates further. Watch for Medicare uptake data in Q1 results — 40 million new beneficiaries is a massive TAM expansion.
For Novo: The Wegovy pill's 170K patient start is encouraging but needs to show it can offset pricing headwinds. Semaglutide patent cliff in emerging markets (Brazil, Canada, China) creates generic competition risk that tirzepatide doesn't yet face. Watch for management stability — two senior departures during a guidance cut is a governance signal.
For the sector: With Big Tech hyperscalers committing $650 billion in AI capex for 2026 and tariff uncertainty prompting scattered guidance withdrawals (Volvo has already pulled its 2026 outlook), the pharma GLP-1 divergence isn't happening in isolation. It's happening in a market that's rewarding clarity and punishing ambiguity.