S&P 500 biggest August 2026 winners: Moderna, software stocks

Moderna emerged as the standout performer in the S&P 500 during August, propelled by groundbreaking results from a late-stage trial of a personalized mRNA cancer vaccine. This development sparked widespread enthusiasm, with CNBC's Jim Cramer calling it "miraculous" and attributing the surge to a "miraculous welcome." Enterprise software stocks also played a significant role in the index's top performers, including Palantir, Veeva Systems, Salesforce, and ServiceNow.

Previous skepticism surrounding the long-term competitiveness of traditional software models, due to rapid AI advancements, led to significant sell-offs. However, the short positions of leveraged hedge fund Situational Awareness, which had bet against software stocks, were unwound, providing a tailwind for these companies. Analyst Jim Cramer likened the impact of the fund's implosion to a "tailwind" for the targeted software stocks.

As August concluded, the effects of this hedge fund collapse were evident in the strong performance of Moderna, enterprise software stocks, and several other individual software companies, such as Salesforce, ServiceNow, and Veeva Systems, all of which rebounded strongly.