Merck & Co., Inc. (MRK) vs Walmart Inc. (WMT)

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.

Founded in 1962, Walmart Inc. has grown into the world’s largest retailer, operating more than 10,700 stores worldwide, including about 4,600 Walmart locations in the United States and roughly 600 Sam’s Club warehouses, while continuing to expand its e-commerce business. The company serves around 270 million customers each week and generated over $680 billion in fiscal 2025 revenue. Walmart’s operations are organized into three reporting segments: Walmart U.S., which accounted for 68% of fiscal 2025 sales, Walmart International at 18%, and Sam’s Club at 14%. In the U.S., nearly 60% of Walmart’s $465 billion in fiscal 2025 revenue came from grocery sales, with about one-quarter generated by general merchandise. Internationally, the company’s business is primarily concentrated in Mexico, with additional emerging exposure to India.