Lost Money on Merck & Co., Inc. Shares? The Law Offices of Frank R. Cruz Investigates Potential Securities Fraud After 1.76% Stock Decline

Investigation centers on the October 22, 2026 news about Merck & Co., Inc.; investors with losses may have potential claims to recover them

LOS ANGELES--(BUSINESS WIRE)--Merck & Co., Inc. ("Merck" or the "Company") investors who lost money may have claims to recover their losses. The Law Offices of Frank R. Cruz today announced it is investigating potential securities fraud claims on behalf of investors in Merck & Co., Inc. (NYSE: MRK), examining whether the Company may have violated the federal securities laws. The investigation centers on the disclosure about Merck & Co., Inc. on October 22, 2026.

If you lost money on Merck & Co., Inc. securities, share your Merck & Co., Inc. loss information with the firm to learn about potentially pursuing a claim to recover your losses.

Merck & Co., Inc. investigation at a glance

• Date of disclosure: October 22, 2026
• Share price decline: $2.64 per share, or 1.76%
• Closing price: $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.

"Merck & Co., Inc. shares dropped 1.76% after it was disclosed on October 22, 2026 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. Our investigation will look at whether investors had complete and accurate information before that disclosure," said Frank R. Cruz of The Law Offices of Frank R. Cruz.

What should Merck & Co., Inc. investors do now?

The Law Offices of Frank R. Cruz is investigating potential claims on behalf of Merck & Co., Inc. investors. Investors who lost money can visit the Merck & Co., Inc. investigation page, email [e-mail], or call 310-914-5007.

If you inquire by email, please include your mailing address, telephone number, and number of shares purchased.

Questions and answers about the Merck & Co., Inc. investigation

Who is eligible? Investors who purchased Merck & Co., Inc. securities and suffered losses may have claims, and can contact the firm to find out whether the Merck & Co., Inc. investigation affects them.

What does a securities fraud investigation involve? In the Merck & Co., Inc. investigation, The Law Offices of Frank R. Cruz is examining whether the Company or its executives may have made false or misleading statements to investors in violation of the federal securities laws.

Is there a lawsuit? This release announces an investigation by The Law Offices of Frank R. Cruz, not a lawsuit. If a securities class action is later filed against Merck & Co., Inc., investors may be able to seek appointment as lead plaintiff.

How are attorneys' fees handled? The Law Offices of Frank R. Cruz works on contingency, so Merck & Co., Inc. investors pay no attorneys' fees up front. Any attorneys' fees and litigation expenses come only from a recovery, if there is one, and require court approval.

Information for whistleblowers

Anyone with non-public information about Merck & Co., Inc. should consider their options to assist the investigation or participate in the SEC Whistleblower Program. The program allows whistleblowers who provide original information leading to a successful SEC enforcement action to receive awards of 10 to 30 percent of the sanctions collected, when those sanctions exceed $1 million. For more information, contact Frank R. Cruz at 310-914-5007 or email [e-mail].

About The Law Offices of Frank R. Cruz

The Law Offices of Frank R. Cruz investigates and prosecutes securities fraud and corporate malfeasance class actions. With nearly 20 years of litigation experience, the firm focuses on complex securities class actions and gives each client personal, one-on-one attention throughout the legal process.

Prior results do not guarantee a similar outcome.

Related links

• Merck & Co., Inc. investigation page, The Law Offices of Frank R. Cruz
• Press Release
• Merck & Co., Inc. SEC filings index, EDGAR
• SEC Whistleblower Program
• The Law Offices of Frank R. Cruz

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