Moderna shares have surged 663% in 2026, closing at $225 on Oct. 9 and temporarily outpacing every other S&P 500 constituent. The rally has been driven not by AI chip demand, but by the company’s cancer vaccine developed with Merck and passive buying after Moderna rejoined the Nasdaq-100.
Investors are still waiting for the full results of the vaccine trial, due Oct. 24. The stock has climbed sharply before detailed efficacy and safety data have been made public.
Late-stage skin cancer trial clears its final hurdle
Moderna, best known for its COVID-19 vaccine, and Merck announced on Aug. 19 that their experimental cancer vaccine for skin cancer patients had met the requirements of a final-stage trial. Moderna shares rose 177% that day, then fell 24% the following session, underscoring the market’s volatile response to the news.
The rally follows a difficult period for the company as sales of its COVID-19 vaccines declined. Moderna cut more than 800 jobs last year, and by mid-August its shares were still nearly 90% below their pandemic-era peak. The stock had already risen 125% in June after the company received approval for a flu vaccine, but remained well below current levels.
The cancer vaccine result has given investors reason to reassess Moderna’s pipeline. Until the full data are released, however, the topline announcement alone does not show the treatment’s efficacy, potential patient population or likely path to commercialization.
Nasdaq-100 return brings passive demand
Moderna rejoined the Nasdaq-100 on Oct. 9. The index tracks the largest non-financial companies listed on Nasdaq. Nasdaq says more than 200 funds follow the index, with combined assets under management exceeding $800 billion.
Index changes typically prompt passive funds to adjust their holdings. Funds tracking the Nasdaq-100 therefore had to buy Moderna shares to reflect the updated membership and weightings, adding another source of demand after the vaccine announcement. The stock gained a further 14% that day.
Reports that the United States could launch a nationwide cancer vaccine initiative in December also drew market attention. The proposed effort was described as similar to the nationwide vaccination push during the COVID-19 pandemic. Its details, scope and potential impact on Moderna’s revenue remain unclear.
Moderna outpaces AI-linked stocks
AI-related companies have led much of the U.S. market’s gains in 2026, but Moderna has temporarily moved ahead of them. SanDisk, a supplier of storage chips for AI data centers, is up 566% this year amid rising demand for AI storage hardware—still short of Moderna’s gain.
The S&P 500 has risen about 14% over the same period. Moderna’s outperformance highlights how sharply its shares have responded to clinical-trial news, expectations for its product pipeline and changes to index membership.
The next key date is Oct. 24, when Moderna and Merck are due to publish the full cancer vaccine trial results. Investors will be looking for data that support the initial reaction, as well as evidence relevant to Moderna’s prospects as it faces declining COVID-19 vaccine revenue and seeks growth from its cancer vaccine and broader pipeline.