Merck Q1 2026 earnings: one-time $9B charge drives net loss as Keytruda sales keep climbing

May 4, 2026 · Published August 7, 2026

Merck's quarterly net loss came from a one-time acquisition accounting charge, not weak sales — Keytruda and newer drug Winrevair both grew, and full-year guidance held steady.

Figures as reported by the company to the SEC for the quarter ended March 31, 2026. Analyst estimates are not part of a filing, so no comparison to expectations is shown.

Key takeaways

• Merck posted a net loss for the quarter, but the loss was driven almost entirely by a one-time $9 billion R&D accounting charge tied to its acquisition of Cidara Therapeutics, a biotech developing a long-acting flu-prevention drug — not by weakness in the core business.
• Keytruda, Merck’s top-selling cancer immunotherapy, remained the main growth driver, with sales up sharply from a year earlier on continued demand in advanced cancers and early uptake of a new under-the-skin injectable version launched this year.
• Winrevair, Merck’s newer drug for a rare lung disease called pulmonary hypertension, saw sales climb steeply from a year ago, a sign the company’s newer products are starting to reduce its reliance on Keytruda.
• The sharp year-over-year drop in trailing profit per share and thin operating margin in the fundamentals largely reflect that one-time acquisition charge flowing through the books, rather than a decline in how profitably Merck’s ongoing drug business is running.
• Merck narrowed its full-year 2026 revenue and adjusted profit guidance ranges slightly upward at the low end, suggesting management’s view of the year ahead is largely unchanged from its prior outlook.
• CEO Rob Davis said the Cidara acquisition “strengthens and complements our expanding respiratory portfolio,” framing the charge as the cost of a strategic bet on a new antiviral drug candidate rather than a one-off setback.
• Coverage noted the loss stemmed specifically from acquisition accounting rules that require certain in-development drug assets to be expensed immediately, which is why a $9 billion deal shows up as a quarterly charge rather than being spread out over time.

Q1 2026 in context

Figures for the quarter ended Mar 2026 and the quarter ended Mar 2025, as reported to the SEC.

How the stock took it

Merck & Co Inc closed at $112.16 on May 1, 2026, the last session before the report, and at $113.15 on May 5, 2026, the first session after it — +0.9% across the report.

Closes from the market's daily record. Each figure spans the report date — from the last session that closed before it to the first that closed after — because a company may report before the open or after the close.

Financial history →

Sources: company report · earnings coverage · verified fundamentals · Merck.com / SEC filing coverage