Merck Stock Hits Near-52-Week Highs on Keytruda Growth

Merck's stock price has reached near-52-week highs in mid-August 2026, driven by strong oncology sales and upbeat full-year guidance. As of August 13, 2026, Merck shares closed at $135.57 on the NYSE, representing a 2.00% gain for that session and placing the stock within a few dollars of its recent 52-week highs.

The company's oncology portfolio remains a central driver of sentiment in 2026, with flagship immuno-oncology therapy Keytruda generating substantial sales in the first half of the year. In fact, Keytruda generated $16.40 billion in sales in the first half of 2026, up 4.2% year over year.

Keytruda's growth is a key factor in Merck's strong year-to-date performance, with shares up more than 26% since January 1, 2026. This outperformance is especially visible when comparing Merck's year-to-date gain against the broader sector and the S&P 500.

The valuation of Merck's stock has also come under scrutiny, with a forward price-earnings multiple of 18.92 times expected earnings above both the industry average and the company's historical valuation. While some analysts have adjusted their near-term expectations due to Keytruda's slowing growth rate, institutional investors and research coverage remain broadly constructive on Merck's long-term trajectory.