Merck (MRK) Stock Today – December 8, 2025: Pipeline Bets, Cidara Deal and Vaccine Policy Risks

Merck & Co., Inc. (NYSE: MRK) is back in the spotlight. As of the afternoon of December 8, 2025, Merck shares trade around $98–99, down about 1% on the day and modestly below their recent 52‑week high of $105.84 reached in late November. That pullback comes after a powerful rebound from a May low near $76, driven by excitement over new cardiovascular and respiratory drugs, plus a $9.2 billion flu‑drug acquisition — even as investors remain focused on the looming 2028 patent cliff for Keytruda and fresh regulatory headwinds. ^[1]

Below is a detailed, news‑ready rundown of today’s key headlines, stock performance, forecasts and expert analysis on Merck stock as of December 8, 2025.

1. Merck stock on December 8, 2025: price, momentum and valuation

Price & move: MRK is trading near $98.6, down about 1.1% versus Friday’s close of $99.72.
52‑week range: $73.31 to $105.84, so the stock is roughly 6–7% below its recent high but well above its 2025 lows.
Market cap & valuation: Merck’s market value is around $250 billion, and its forward P/E is about 11×, below many large‑cap pharma peers and the broader market. ^[2]

Over the past couple of months, sentiment has clearly improved:

Motley Fool notes that the stock has swung from more than $130 in March 2024, down to about $76 in May 2025, and back to “a little more than $100” recently, highlighting a “wild ride” for shareholders. ^[3]
Zacks flags Merck among “bigwigs” with double‑digit returns over the past month, as investors re‑rate the name on pipeline progress and M&A. ^[4]

Today’s dip is tied less to fundamentals and more to policy and legal headlines, particularly around vaccines and Keytruda (more on those below).

2. Today’s big headline: U.S. hepatitis B vaccine policy shift hits sentiment

The most immediate news weighing on Merck today is a major change in U.S. hepatitis B vaccination policy:

On December 5, the CDC’s Advisory Committee on Immunization Practices (ACIP), now appointed by Health and Human Services Secretary Robert F. Kennedy Jr., voted to scrap the universal recommendation that all newborns get a hepatitis B shot at birth. Instead, a birth‑dose is recommended only for infants whose mothers test positive; everyone else is essentially told to decide later with their doctor. ^[5]
Merck, whose Recombivax HB has been a staple of the U.S. pediatric schedule, said it is “deeply concerned,” arguing the universal birth dose led to a 99% drop in acute hepatitis B in children and young adults and has prevented hundreds of thousands of infections and tens of thousands of deaths. ^[6]
Reuters reports Merck and GSK shares both fell about 1% after the vote, reflecting worries about lower long‑term demand for newborn hepatitis B shots. ^[7]

Zacks’ “Company News for Dec 8, 2025” likewise highlights Merck’s stock among the day’s notable decliners, citing the ACIP shift as a key pressure point. ^[8]

Impact for investors:
Hepatitis B vaccines are not a top‑three product for Merck — Keytruda, Gardasil and now newer launches like Winrevair and Capvaxive dwarf Recombivax in revenue — but the ACIP move:

Undermines a long‑standing public‑health success story,
Raises questions about future U.S. vaccine policy under the current administration, and
Adds headline risk for vaccine makers at a time when drug pricing and coverage are already politically sensitive.

Near‑term earnings impact should be modest, but the policy change reinforces that regulatory and political risk is real even for established vaccine franchises.

3. Institutional flows: mixed but still strongly owned

Fresh 13F‑related headlines today show mixed institutional positioning in Merck:

Gabelli Funds LLC trimmed its Merck stake by about 6.7% in Q2. ^[9]
SVB Wealth LLC cut its position by roughly 40% in the same period. ^[10]
Ossiam, by contrast, boosted its holdings by 193%, substantially increasing its exposure. ^[11]

Despite some profit‑taking, third‑party data shows Merck remains heavily institutionally owned (around three‑quarters of shares), and valuations are still near the lower end of their 10‑year P/E range, which some value investors view as an opportunity. ^[12]

4. Q3 2025 earnings: Keytruda, Winrevair and Capvaxive carry the quarter

Merck’s latest numbers, released October 30, frame the fundamental backdrop for today’s newsflow:

Q3 2025 revenue:$17.3 billion, up 4% year over year (3% ex‑FX). ^[13]
Keytruda (oncology): Sales rose 10% to $8.1 billion, accounting for ~47% of total revenue. ^[14]
Winrevair (sotatercept for PAH): Sales reached $360 million, up 141%, signaling rapid uptake. ^[15]
Capvaxive (pneumococcal PCV21): Posted $244 million in Q3 sales as adult uptake ramps. ^[16]
Gardasil/Gardasil 9 (HPV): Sales fell 24% to $1.7 billion, hurt by weak demand and halted shipments to China. ^[17]
Animal Health: Up 9% to $1.6 billion. ^[18]

On the bottom line:

GAAP EPS:$2.32, up sharply year‑on‑year; non‑GAAP EPS:$2.58, beating expectations. ^[19]
Management narrowed 2025 revenue guidance to $64.5–65.0 billion and raised EPS guidance to $8.93–8.98 per share. ^[20]

Despite the beat, the stock sold off on the day as the market focused on Gardasil weakness and the Keytruda concentration risk, not the solid performance from newer products.

5. The growth engine: Winrevair, Capvaxive, Verona and Cidara

Winrevair: a flagship beyond oncology

Winrevair, acquired through Merck’s 2021 Acceleron deal, is rapidly becoming a pillar of the post‑Keytruda strategy:

It’s now approved in the U.S., EU and other major markets for pulmonary arterial hypertension (PAH) and had already generated hundreds of millions in sales earlier this year. ^[21]
On October 27, 2025, the FDA expanded Winrevair’s label to explicitly include improvement in exercise capacity and reduction in major clinical‑worsening events based on the Phase 3 ZENITH trial. ^[22]
Barron’s recently highlighted that Winrevair could top $5.5 billion in annual sales by 2030, up from just over $400 million last year. ^[23]

Guggenheim used new Winrevair data from the CADENCE trial (in a complex heart‑failure‑related pulmonary hypertension population) to justify raising its Merck price target to $122 from $104, calling Winrevair a >$12 billion peak‑sales opportunity when probability‑adjusted across indications. ^[24]

Capvaxive: next‑generation pneumococcal vaccine

Capvaxive (PCV21) is Merck’s answer to Pfizer’s Prevnar franchise:

The vaccine was approved in the U.S. in June 2024 as a 21‑valent conjugate vaccine for adults, designed specifically around the serotypes that cause the majority of invasive pneumococcal disease in adults and including eight serotypes not covered by other PCVs. ^[25]
Regulators and experts note that Capvaxive covers about 80%+ of strains causing invasive disease in adults 50 and older, significantly more than PCV20. ^[26]
In September, a late‑stage study showed strong immune responses in high‑risk children and teens, supporting potential label expansion into pediatric populations. ^[27]

Capvaxive is still small at $244 million in Q3 sales, but its long patent tail and global expansion potential make it one of the key building blocks of Merck’s 2030s revenue plan. ^[28]

Verona Pharma: Ohtuvayre for COPD

Merck has also deepened its respiratory bet with a major acquisition:

In July 2025, Merck agreed to buy Verona Pharma for about $10 billion, paying $107 per ADS — a 23% premium — to acquire Ohtuvayre (ensifentrine), a first‑in‑class maintenance treatment for COPD. ^[29]
The deal closed on October 7, 2025, and Merck now fully owns Ohtuvayre, which the FDA approved in 2024 as the first novel inhaled COPD maintenance therapy in more than 20 years. ^[30]
Analysts estimate Ohtuvayre could deliver $3–4 billion in peak annual sales, with additional upside from potential use in non‑cystic fibrosis bronchiectasis. ^[31]

Merck expects the Verona deal to clip non‑GAAP EPS by about $0.16 in the first year due to amortization and financing, but management and outside analysts see it as a highly strategic, multi‑year growth asset. ^[32]

Cidara Therapeutics: a $9.2 billion bet on flu prevention

The newest piece of the puzzle is Merck’s planned acquisition of Cidara Therapeutics:

Announced November 14, 2025, Merck will pay $9.2 billion in cash to acquire Cidara and its lead asset CD388, a long‑acting, strain‑agnostic antiviral designed to provide season‑long protection against influenza in high‑risk populations. ^[33]
CD388 has shown up to 76% protection over 24 weeks in mid‑stage studies and has FDA Breakthrough Therapy and Fast Track designations, which could speed approval. ^[34]
Merck told investors it sees a commercial opportunity exceeding $5 billion annually for CD388, with around 110 million Americans potentially eligible and minimal need for CDC vaccine‑panel review since the product is an antiviral, not a vaccine. ^[35]

The Cidara deal, expected to close in Q1 2026, will reduce earnings by about $0.30 per share in year one but materially strengthens Merck’s infectious‑disease portfolio into the 2030s. ^[36]

6. Legal and regulatory headwinds: Keytruda SC injunction in Germany

Alongside the positive pipeline news, investors are watching a new legal front:

On December 4, Halozyme Therapeutics announced that a German court granted a preliminary injunction against Merck’s subcutaneous Keytruda formulation, citing “imminent infringement” of Halozyme’s European hyaluronidase (MDASE) patents. ^[37]
The ruling blocks Merck from selling subcutaneous Keytruda in Germany for now; the traditional IV version is not affected. ^[38]
Merck is expected to challenge the decision, but the case introduces uncertainty around the European rollout of Keytruda QLEX, the new subcutaneous formulation approved in the U.S. in 2025 for most adult solid‑tumor indications. ^[39]

Given that Germany is an important oncology market and subcutaneous formulations often enjoy higher convenience‑driven share, this injunction is not immaterial, though the global revenue impact is likely modest in the near term. The bigger issue is that it highlights patent‑complexity risk around Merck’s next‑generation formulations.

7. The Keytruda question: new products vs. 2028 patent cliff

Keytruda remains at the center of every Merck investment debate:

It generated $8.1 billion of Q3 revenue, roughly half of Merck’s pharmaceutical sales, and is approved for 20+ cancer types. ^[40]
U.S. patent protection begins to expire in 2028, with analysts modeling double‑digit percentage revenue declines by 2029–2030 as biosimilars enter. ^[41]

Recent commentary has turned more constructive, however:

A Zacks piece titled “Can Merck’s New Products Aid Growth as Keytruda LOE Test Looms?” argues that Capvaxive, Winrevair and other launches can significantly offset the eventual Keytruda erosion and support long‑term growth. ^[42]
A December 7 Motley Fool article notes that while Keytruda’s dependence is a “double‑edged sword,” Merck now believes its pipeline could collectively generate more than $50 billion in annual revenue by the mid‑2030s, more than replacing Keytruda’s contribution in aggregate. ^[43]

That pipeline, plus the Verona and Cidara acquisitions, is exactly what has driven the stock’s ~30% rebound from its spring lows and a string of recent analyst upgrades.

8. What Wall Street is saying: targets and ratings

Analyst consensus and price targets

Different services paint a consistent picture: cautious but increasingly bullish.

TipRanks: 15 Wall Street analysts rate Merck a “Moderate Buy” with 8 Buys, 7 Holds, 0 Sells. The average 12‑month price target is $109.36, implying about 9.7% upside from a reference price of $99.72; targets range from $82 to $139. ^[44]
StockAnalysis: The same 15‑analyst cohort assigns a “Buy” rating with an average target of $110.33, about 11.9% above the last price, and a high target of $125. ^[45]
Business Insider / Markets Insider: Across a broader group of 36 analysts, the median target is $121.72 with a high of $155 and low of $84 — roughly 24% upside from a last price near $98. ^[46]

Add in Guggenheim’s fresh $122 target and Buy rating, driven by Winrevair’s expanded opportunity, and the Street’s central case is that Merck has 10–25% upside over the next year, assuming its pipeline continues to execute. ^[47]

Style scores and fundamental view

Zacks recently called Merck “a top growth stock for the long term”, even while keeping it at a Zacks Rank #3 (Hold):

Merck carries a VGM score of A and a Growth score of B, with consensus calling for ~17% earnings growth in fiscal 2025.
Eight analysts have raised their 2025 EPS estimates in the last 60 days, pushing the Zacks consensus to about $8.98 per share, and Merck has delivered an average earnings surprise of roughly 5%. ^[48]

9. Dividend profile: one of the Dow’s higher yields

For income‑focused investors, Merck remains a dividend workhorse:

Merck recently increased its quarterly dividend to $0.85 per share, with the next payment scheduled for January 8, 2026 and an ex‑dividend date of December 15, 2025. ^[49]
At today’s share price, that works out to a dividend yield around 3.4–3.5%, with about 14 years of consecutive dividend growth and a payout ratio in the low‑40% range. ^[50]
Motley Fool’s recent piece on the three highest‑yielding dividend stocks in the Dow lists Merck alongside Chevron, with Merck’s yield pegged at roughly 3.4%. ^[51]

Combined with modest share buybacks, Merck’s total shareholder yield is estimated at just over 4%, offering a solid income foundation while investors wait for the pipeline to mature. ^[52]

10. Voices from the Street: Jim Cramer and Motley Fool

Media commentary has become noticeably more positive in early December:

On December 8, Insider Monkey highlighted Jim Cramer’s bullish remarks, quoting him saying “The people who run this company are not idiots,” and praising Merck’s years‑long effort to prepare for a post‑Keytruda world via acquisitions like Verona. He points to analysts who now see over $20 billion in de‑risked peak sales added in just the last 3–6 months and calls Merck a “very cheap stock” with a roughly 3.4% yield entering a “catalyst‑rich” 12–18 months. ^[53]
Motley Fool’s “Merck’s Stock Is Suddenly Soaring, But Is the Struggling Healthcare Giant a Buy?” notes that despite the recent 30% bounce from September lows, shares still trade at less than 12× next‑year earnings, with a ~3.3% forward yield, and argues that investors may be over‑dramatizing the 2028 patent cliff given the breadth of Merck’s pipeline and the arrival of products like Keytruda QLEX, Winrevair, Capvaxive and future Cidara launches. ^[54]
Another Motley Fool piece, “Is This Pharmaceutical Giant a Buy After a Major Acquisition?”, frames the Cidara deal as a key catalyst behind a roughly 27% one‑month move in the stock, suggesting that Merck’s aggressive M&A could finally be changing the narrative from “Keytruda risk” to “multi‑pillar growth story.” ^[55]

Overall, mainstream commentary is moving from defensive, risk‑focused to cautiously optimistic, especially after Q3 earnings and the Winrevair/Cidara news.

11. Key risks to watch

Even with improving sentiment, investors shouldn’t ignore the risk side of the ledger:

Keytruda concentration and patent expiry (2028)
- Nearly half of Merck’s revenue still comes from Keytruda, and analysts expect meaningful sales declines starting around 2029 as biosimilars arrive. ^[56]
Gardasil and vaccine demand volatility
- Gardasil sales fell 24% in Q3, and Merck has paused shipments to China through at least the end of 2025 due to weak demand, prompting a cost‑cutting plan targeting $3 billion in annual savings by 2027. ^[57]
- The hepatitis B policy change by ACIP heightens policy‑risk concerns for vaccine makers more broadly. ^[58]
Legal and IP risk
- The Halozyme injunction against subcutaneous Keytruda in Germany underscores how critical formulation patents and partnerships can be for next‑generation biologics. ^[59]
Integration and execution risk on big deals
- The Verona and Cidara acquisitions together represent nearly $20 billion of capital deployment and will temporarily depress EPS. Realizing projected multi‑billion peak sales from Ohtuvayre and CD388 will require flawless clinical, launch and market‑access execution. ^[60]

12. Merck stock outlook: is MRK a buy, hold or sell now?

Putting it together as of December 8, 2025:

Fundamentals: Q3 showed steady top‑line growth, big contributions from Keytruda, Winrevair and Capvaxive, and strong margin expansion, plus raised EPS guidance. ^[61]
Pipeline & M&A: Merck has quietly assembled a multi‑legged growth engine across oncology, cardiovascular/PAH, respiratory disease and infectious disease (Winrevair, Capvaxive, Ohtuvayre, CD388 and others). ^[62]
Valuation: Shares trade around 11× forward earnings, a discount to many large‑cap healthcare names, while offering a 3.4–3.5% dividend yield and mid‑teens earnings‑growth expectations. ^[63]
Street view: Most Wall Street analysts rate the stock Buy or Moderate Buy, with average price targets in the $109–110 range and some houses now at $120–122 based on Winrevair and the broader pipeline. ^[64]

For long‑term investors who can tolerate pharma‑sector volatility and regulatory risk, Merck today looks like:

A reasonably valued, dividend‑paying blue chip,
With credible pipeline and M&A‑driven paths to offset Keytruda’s 2028 patent cliff,
But still exposed to headline risk (policy changes, patent fights, and China demand) that can produce sharp short‑term swings in the share price.

This article is information only and not financial advice. Whether MRK is a buy, hold or sell for you depends on your time horizon, risk tolerance, portfolio mix and view on drug‑pricing politics. If you’re considering an investment, it’s worth:

Stress‑testing your thesis under more severe Keytruda erosion,
Considering how much regulatory risk you’re comfortable underwriting, and
Comparing Merck’s risk‑reward to other large‑cap pharma and diversified healthcare names.

Still, as of December 8, 2025, the balance of news, forecasts and expert analysis suggests that Merck is no longer just a Keytruda story — and that is exactly what the market has started to price in.