Novo Nordisk's (NVO  ) nearly 11% pre-market drop on Monday and subsequent 9% dip at market open, in the aftermath of disappointing topline results from its evoke/evoke+ Alzheimer's trials, is more than a pipeline setback. It's a stress test for healthcare ETFs that have quietly become GLP-1 momentum vehicles. With two years of outperformance powered by Novo's Ozempic and Wegovy, and Eli Lilly's (LLY  ) Mounjaro and Zepbound, many ETFs now live and die by the swings of just two companies: Novo and Eli Lilly.

Where ETF Exposure Is Heaviest

The Roundhill GLP-1 & Weight Loss ETF (OZEM  ) sits squarely at the center of Monday's shock. The fund's top weights - Eli Lilly at 18.72% and Novo Nordisk at 13.23% - mean that more than one-third of the ETF is tied directly to the GLP-1 duopoly. OZEM has benefited enormously from the sector's runaway rally, but Novo's sudden decline shows the flip side: thematic funds concentrated in just a few dominant players can amplify volatility when one of them hits a speed bump. Still, given Lilly's broader revenue engines, OZEM may remain more resilient than its high concentration suggests.

The VanEck Pharmaceutical ETF (PPH  ) is sensitive to Elli Lilly and Novo Nordisk, making the fund an accidental bet on the GLP-1 duopoly. GLP-1 names have been key return drivers in this ETF, and Monday's selloff underlines how inextricably linked the ETF's fate is to both Novo and Lilly.

iShares U.S. Pharmaceuticals ETF (IHE  ): Lilly accounts for meaningful weight (27%) in the ETF, making the fund heavily concentrated in one stock. When Lilly stumbles, the impact ripples quickly. Not necessarily a bet on Novo, but this ETF highlights the problem of concentration risk.

Even broad sector funds, such as Health Care Select Sector SPDR Fund (XLV  ), which are market-cap weighted, are not immune. Lilly's rocketing to a trillion-dollar market cap has given the stock oversized influence.

Why Lilly-Dominant ETFs May Be Safer Than They Look

Yet here's the kicker: ETFs heavy on Eli Lilly could end up in a position of strength.

Thanks to the extraordinary success of Mounjaro and Zepbound, which have generated $25 billion in the first nine months of 2025, Lilly became the first healthcare company in history to reach a $1 trillion valuation. But unlike Novo, Lilly is not a one-pillar company.

Its broader portfolio is firing on all cylinders:

  • Verzenio (oncology) and Taltz (immunology) continue robust growth.
  • Newer launches - Omvoh, Ebglyss, Jaypirca, Kisunla - meaningfully adding to revenues.
  • A spate of M&A activity focusing on ophthalmology, oncology, gene therapy, and cardiovascular disease is diversifying the future pipeline.
  • Also, late-stage pipeline candidates like orforglipron -ahead of oral GLP-1 and the tri-agonist retatrutide would indicate that Lilly is extending their lead in next-generation obesity treatments.
For OZEM, PPH, IHE, and XLV - among other ETFs - this multi-engine growth story means Lilly-heavy exposure remains relatively secure, even if the GLP-1 trade experiences short-term hiccups.

Meanwhile, Novo has to grapple with a more complex storyline:

  • Narrowed GLP-1 growth expectations.
  • Trial failures outside of its core obesity franchise.
  • Trump's push to lower "fat-loss drug" prices.
  • an FDA rejection of its multi-dose Wegovy device
  • Intensifying competition from Lilly, Viking Therapeutics, and Pfizer's $10 billion Metsera acquisition.
  • Even as it works on oral Wegovy and next-generation combinations like CagriSema and amycretin, Novo's expectations for revenue growth have moderated.
The Takeaway For ETF Holders

The GLP-1 boom has reshaped healthcare ETFs, supercharging returns but also amplifying risk. The stumble by Novo Nordisk does not in any way derail the obesity blockbuster trend, but it is a sharp reminder that concentration cuts both ways. For investors in pharma and healthcare ETFs, understanding who carries more Novo risk versus Lilly resilience may matter now more than ever.