Merck's WW1 split into a US and German company

In the heart of 17th-century Darmstadt, a small apothecary laid the foundation for what would become one of the world’s oldest and most resilient science and technology companies: Merck. Founded in 1668 by Friedrich Jacob Merck, the family-owned pharmacy quietly served its local clientele for generations. It wasn’t until the 19th century, though, that Merck transformed from a local chemist shop into a global enterprise, catalyzed by industrialization and a rising demand for purified chemicals.

By the late 1800s, Merck had become a pioneer in alkaloid production, supplying morphine, cocaine, and other plant-based compounds to pharmaceutical companies and physicians worldwide. Its early success wasn’t just about making drugs—it was about precision, quality, and trust. Merck’s scientific rigor earned it an international reputation, and subsidiaries began to pop up across the globe, including one in New York in 1891, which would later become the now-independent Merck & Co.

World War I fractured the business. The U.S. government seized Merck’s American subsidiary, permanently splitting the company in two: the original German Merck, headquartered in Darmstadt, and the American Merck & Co., which remains a separate entity to this day. It was one of the first examples of geopolitics forcing a corporate identity crisis that still confuses people over a century later.

Merck’s U.S. subsidiary was seized in 1917, during World War I, under the Trading with the Enemy Act. The U.S. government took control of Merck & Co., which had been established by the German parent company in 1891. After the seizure, it was sold off and became an independent American company, fully separate from the original Merck in Darmstadt.

That split still causes confusion today, with Merck & Co. operating as “Merck” in the U.S. and Canada, and the original Merck KGaA using the name “Merck” elsewhere, but “EMD” (for Emanuel Merck, Darmstadt) in North America.

Merck & Co. in the U.S. has since become a pharmaceutical giant in its own right. Headquartered in Rahway, New Jersey, Merck & Co. is one of the largest pharmaceutical companies globally, known for developing a wide range of innovative drugs and vaccines, including the cancer immunotherapy Keytruda, HPV vaccine Gardasil, and treatments for diabetes, infectious diseases, and cardiovascular conditions. It has played a leading role in addressing public health challenges, from the COVID-19 pandemic to antimicrobial resistance. Despite the shared name and origin, the two Mercks are fierce competitors and operate entirely independently.

Meanwhile, Merck Darmstadt doubled down on science. Throughout the 20th century, it diversified beyond pharmaceuticals into performance materials, life sciences, and electronics. While other pharma giants chased blockbuster drugs, Merck took a different path: enabling innovation behind the scenes. It became a key supplier to labs, biotech startups, and chipmakers—especially after acquiring Millipore in 2010 and Sigma-Aldrich in 2015. Quietly, Merck became the picks-and-shovels player of multiple revolutions: the biotech boom, the semiconductor surge, and now, the AI hardware race.

Still privately held by the Merck family—now in its 13th generation—the company blends tradition with modernity in a way that feels rare in corporate life. Today, with over 60,000 employees and operations in more than 60 countries, Merck remains more global than German. But its soul is still in Darmstadt, where glass-and-steel labs now stand on the site of that old apothecary.

Merck KGaA is a publicly traded company, listed on the Frankfurt Stock Exchange under the ticker symbol MRK. However, it’s not fully public: approximately 30% of its shares are publicly traded, while the remaining 70% are held by the Merck family through their holding company, E. Merck KG.

This structure, known as a Kommanditgesellschaft auf Aktien (KGaA) , allows the Merck family to retain strategic control while still accessing capital markets. So, while it’s publicly listed, it’s also majority family-owned.

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