Why is Moderna stock rallying today?

Moderna's stock surged 150% in August after positive trial results for its personalized mRNA cancer vaccine with Merck's Keytruda. The company's revenue peaked at $18B with its COVID-19 vaccine but faced declines due to reduced demand. Moderna has since expanded its pipeline, including approvals for updated COVID-19, RSV, and flu vaccines. The stock's recent gains may be priced in, and investors should consider waiting for a potential pullback.

Moderna (MRNA) shares surged 156% in August, driven by positive clinical trial results for its melanoma therapy and FDA approval for updated COVID-19 vaccines. The company's therapy, in partnership with Merck, met primary and secondary endpoints, showing improvement over Keytruda alone. Moderna also reported increased hedge fund holdings and highlighted the large market potential for its melanoma treatment.

Moderna Inc (MRNA) shares rose 0.71% to $138.97 on August 31, 2026, with bullish options activity. The company's P/S ratio is 24.69, above its historical median of 8.4, indicating high growth expectations. GuruFocus' GF Value™ suggests MRNA is 476.4% overvalued. Insider activity shows $47.8M in selling over 12 months, while guru holdings are mixed.

FDA approved updated Covid vaccines from Pfizer (Comirnaty XFG) and Moderna (Spikevax, mNEXSPIKE) targeting the XFG variant for the 2026-2027 season. Approvals were based on mouse studies and prior human data, with human trials for the new formulations not yet started. The shots are approved for specific age groups and high-risk individuals. Both companies expect rapid availability. The approvals follow substantial government contracts and include warnings for myocarditis and pericarditis.

Merck & Co. and Moderna developed a personalized cancer vaccine, customized for each patient's tumor genome, to be used with Merck's Keytruda. The FDA granted Breakthrough Therapy designation in 2023. Phase 3 trials showed a 44% reduction in recurrence risk for melanoma patients. The companies are also exploring its use in lung, renal cell, and bladder cancers.

Moderna (MRNA) and Merck (MRK) stocks surged after announcing positive late-stage melanoma vaccine trial results. The trial combined Moderna's mRNA technology with Merck's Keytruda drug. Analysts from Bank of America and Morgan Stanley raised price targets for Moderna, citing the vaccine's potential. Merck reported strong sales growth for Keytruda and other drugs, but posted a net loss in Q2. Hedge fund activity and short interest were noted for both companies.