Merck KGaA warned that adjusted operating profit margins will decline to around 28% in 2026 from 28.9% in 2025 as patent losses on its multiple sclerosis drug Mavenclad and currency headwinds take effect. The Darmstadt-based company reported net sales of €21.10 billion in 2025, with organic growth of 3.1% despite a 0.3% overall decline.

Operating cash flow fell 14.3% to €3.93 billion while profit after tax dropped 6.1% to €2.62 billion. A U.S. appeals court affirmed the invalidity of two key patents protecting Mavenclad's dosing regimen in October, opening the door to generic competition for the drug that generated €1.19 billion in 2025 sales. Merck completed its €3 billion acquisition of SpringWorks Therapeutics in July but cited earnings dilution from the transaction as a primary driver of a 3.4% decline in adjusted earnings per share.

The company's Life Science division, which generates 42% of group sales, posted organic growth of 4%, led by Process Solutions at 10.7%. Electronics, at 17% of sales, saw Semiconductor Materials grow 8.2% organically on AI-driven demand. Merck shares fell 12.4% in 2025 to €122.60, and the dividend held flat at €2.20 per share.