Merck Shares Drop 3.3% Amid Overvaluation Concerns

Shares of Merck & Co Inc (MRK) dropped 3.3% on October 5, 2026, closing at $139.54. This decline adds to a 6.6% decrease over the past month and a 6.2% fall over the past week, despite the stock's year-to-date gain of 35.3% and a 61.0% year-over-year increase.

The current price is significantly above the GF Value™ estimate of $120.92, indicating the stock is 15.4% overvalued. GuruFocus's GF Valuation label categorizes MRK as "Modestly Overvalued," suggesting caution due to potential price corrections if future growth expectations are not met.

MRK's P/E ratio of 111.5x is substantially higher than its 5-year median P/E of 20.2x, reinforcing concerns about overvaluation. The GF Score™ of 79/100 highlights strong profitability but weaker financial strength and momentum.

Insider activity shows $71.4 million in stock sales over the past 12 months, with no insider buying reported. Among gurus, 26 hold positions, with 8 adding and 16 trimming their holdings, reflecting a mixed sentiment.