Merck Stock Vs. LLY: Why Is The Slower Grower More Expensive?

Trefis Team

Thu, September 10, 2026 at 10:10 PM GMT+3 4 min read

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In the high-stakes world of big pharma, the slower-growing giant now commands the higher price, forcing investors to decide what that premium is truly buying.

In the pharmaceutical industry, Merck (MRK) and Eli Lilly (LLY) are direct rivals competing for the same healthcare dollars. Yet right now, the market presents investors with a stark valuation mismatch. For every dollar of operating profit, the market charges 52.2 times for Merck, but only 25.3 times for Eli Lilly, the company that is growing dramatically faster.

This is a complete reversal from a year ago, when Merck was the cheaper of the two. The positions have flipped. The question for any investor watching these stocks is what has changed to justify Merck now trading at a premium it did not previously command, and what exactly that premium buys you today.

Is Merck's pipeline finally getting its due?

Merck's optic of a premium is partly mathematical—the result of a near-65% collapse in trailing operating income—but the market's willingness to look past that trough rests entirely on pipeline optimism. Management has highlighted more than "$70 billion of commercial opportunity" expected from over 20 new products designed to transform the portfolio. This is the company's answer to the eventual patent expiration of its blockbuster, Keytruda.

Recent progress suggests this is more than just a forecast. The FDA recently approved Lipfendra, the "first and only oral PCSK9 inhibitor," a major new drug for high cholesterol.

The company also announced positive Phase III results for its antibody-drug conjugate sac-TMT and for tulisokibart, a treatment for ulcerative colitis. This shift in valuation raises a critical question for investors, which some are already asking: is Merck stock pricing in a post-Keytruda future too soon? The premium suggests the market is betting that this pipeline is real, diversified, and arriving on schedule.

The key numbers side by side, today:

OpInc = Operating Income, P/OpInc = Price To Operating Income Ratio

And the same comparison exactly a year ago, so you can see which way the mismatch has been moving:

OpInc = Operating Income

The price of that bet is today's explosive growth elsewhere.

Paying that premium for Merck's future, however, means forgoing the demonstrated momentum Eli Lilly offers right now. Lilly's appeal extends beyond its lower valuation; the business is firing on all cylinders, with revenue growing 49.6% over the last twelve months compared to 4.6% for Merck. That is not a small gap.

Lilly's management is signaling more to come, having raised its forward revenue guidance at its latest report. The company continues to build on its strengths, recently announcing Phase III data evaluating Verzenio in combination with endocrine therapy. For investors who see the potential in the broader healthcare space but prefer not to pick a single winner, a broad sector fund like XLV offers exposure to both companies. But for those choosing between the two, the tradeoff is sharp: Lilly offers powerful, proven growth today.

The choice comes down to two different growth stories.

Ultimately, the decision between Merck and Eli Lilly hinges on which growth narrative an investor finds more compelling. Merck's premium is the price for a story of transformation, a bet that a deep and diversifying pipeline will successfully navigate the company into the next decade. Eli Lilly offers a story of rapid scale, where investors buy into the explosive growth of its current blockbuster portfolio.

The tradeoff is between Merck's de-risking future and Lilly's high-momentum present. The key test for Merck will be its ability to execute on its new opportunities. The most immediate thing to watch is the commercial ramp of its new launches, particularly how quickly the recent FDA approval for Lipfendra translates into market access and sales. Whether that execution can justify its new premium is a decision the market, and the investor, has yet to finalize.

Want to stack them up side by side yourself?

You can line Merck and Eli Lilly up directly on the Merck peer comparison, weigh them on valuation, growth, margins, and returns, and swap in any other Pharmaceuticals names you hold.

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