Investigation comes after an October 22, 2026 report concerning Merck & Co., Inc.; shareholders who suffered losses may have claims to recover them

Investors who suffered losses on Merck & Co., Inc. ("Merck" or the "Company") stock may have claims to recover those losses. The Law Offices of Howard G. Smith today reported that it is conducting a securities fraud investigation on behalf of Merck & Co., Inc. (NYSE: MRK) investors into whether the Company may have violated the federal securities laws. The investigation comes after an October 22, 2026 disclosure concerning Merck & Co., Inc.

Investors with losses on Merck & Co., Inc. securities can contact The Law Offices of Howard G. Smith about the Merck & Co., Inc. investigation to learn about potentially pursuing claims to recover their losses.

Key facts for Merck & Co., Inc. investors

• Disclosure: October 22, 2026
• Stock drop: $2.64 per share, or 1.76%
• Close after the drop: $147.24 on October 22, 2026

What happened?

On October 22, 2026, an early release of closely watched clinical trial results for Moderna and Merck’s joint experimental cancer vaccine appeared on medical news website Oncology Central but were taken down shortly afterward. According to the briefly published report, combining the Moderna and Merck’s personalized mRNA cancer vaccine with Merck’s blockbuster immunotherapy Keytruda reduced the risk of melanoma returning or death by 42% compared with Keytruda alone.

On this news, Merck stock fell as much as $2.64 or 1.76%, to close at $147.24 on October 22, 2026.

"On October 22, 2026, it was reported that Oncology Central had briefly published, then removed, an early report stating that Moderna and Merck's personalized mRNA cancer vaccine combined with Keytruda reduced the risk of melanoma recurrence or death by 42% versus Keytruda alone, and Merck & Co., Inc. stock lost 1.76% of its value. Our investigation is focused on whether shareholders had the full story before that report," said Howard G. Smith of The Law Offices of Howard G. Smith.

Next steps for Merck & Co., Inc. investors

The Law Offices of Howard G. Smith is examining potential claims on behalf of Merck & Co., Inc. investors. Investors with losses can visit the firm's website, email howardsmith@howardsmithlaw.com, or call (215) 638-4847 to discuss the Merck & Co., Inc. investigation.

Common questions from Merck & Co., Inc. investors

Who is eligible? Merck & Co., Inc. investors who bought securities and lost money may have claims, and can reach out to the firm to learn whether the Merck & Co., Inc. investigation affects them.

What is a securities fraud investigation? Through the Merck & Co., Inc. investigation, The Law Offices of Howard G. Smith is reviewing whether the Company or its officers may have made false or misleading statements to investors in violation of the federal securities laws.

Has a lawsuit been filed? This release announces an investigation of Merck & Co., Inc. by The Law Offices of Howard G. Smith, not a lawsuit. If a securities class action is later filed, Merck & Co., Inc. investors may be able to seek appointment as lead plaintiff.

Does it cost anything? The Law Offices of Howard G. Smith works on contingency, meaning Merck & Co., Inc. investors owe no attorneys' fees out of pocket. Any attorneys' fees and litigation expenses are paid solely from a recovery, if achieved, and require court approval.

Whistleblower notice

Individuals with non-public information about Merck & Co., Inc. should consider their options to help the investigation or take part in the SEC Whistleblower Program. Whistleblowers who provide original information that leads to a successful SEC enforcement action may receive awards of 10 to 30 percent of the sanctions collected, when those sanctions exceed $1 million. For more information, contact Howard G. Smith at (215) 638-4847 or email howardsmith@howardsmithlaw.com.

About The Law Offices of Howard G. Smith

The Law Offices of Howard G. Smith has helped injured investors recover their money for more than 15 years. The firm prosecutes securities fraud, takeover, and derivative litigation against public companies and their officers, directors, and advisors in federal and state courts nationwide, and has helped clients recover hundreds of millions of dollars in losses. Clients speak directly with a lawyer, who will promptly answer any question.

Prior results do not guarantee a similar outcome.

Related links

• Merck & Co., Inc. investigation, The Law Offices of Howard G. Smith
• Press Release
• Merck & Co., Inc. SEC filings index, EDGAR
• SEC Whistleblower Program
• The Law Offices of Howard G. Smith

This press release may be considered Attorney Advertising in some jurisdictions under the applicable law and ethical rules.

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