Merck & Co., Inc. (MRK) vs Visa Inc. (V)

Merck & Co., Inc. develops pharmaceutical products across multiple therapeutic areas, including cardiometabolic disorders, oncology, and infectious diseases. In cancer treatment, its immuno-oncology portfolio, led by Keytruda, represents a significant driver of total revenue. The company also maintains a strong vaccines business focused on preventing pediatric illnesses, alongside Gardasil for human papillomavirus. In addition, Merck markets animal health products. Geographically, 47% of the company’s sales come from its U.S. human health segment, which includes pharmaceuticals and vaccines.

Visa Inc. is the world’s largest payment processor. In fiscal 2025, the company handled nearly $17 trillion in total payment volume. Visa operates in more than 200 countries and territories and processes transactions in over 160 currencies. Its network is capable of handling more than 65,000 transactions per second.