Top 10 Best-Performing US Stocks in August: Moderna Surges 156%, Palantir Leads AI Software Stocks

TradingKey - In August 2026, the momentum behind the U.S. stock rally broadened significantly. While rising oil prices and strong earnings from tech giants like Nvidia took center stage, the market leaders that month were not limited to energy and semiconductors, as biotech, enterprise software, gold, media, and AI server stocks all posted substantial gains.

The S&P 500 Index gained 2.6% in August, with roughly half of its constituents recording positive returns. Among them, 86 stocks surged by at least 10% during the month, and 23 stocks rose by at least 20%, signaling that market capital is rotating from a handful of tech giants into a broader range of industries.

Moderna Leads Gains as Software Stocks Take Half the Spots

Moderna (MRNA) led S&P 500 components with a 156% gain, surging 375.9% year-to-date. Palantir (PLTR) followed closely behind, rising 51.5% in August, as enterprise software stocks overall extended their previous recovery.

Among the top 10 gainers, Veeva Systems (VEEV), Salesforce (CRM), ServiceNow (NOW), and Gartner (IT) are all associated with enterprise software or digital services. Salesforce, in particular, rose 40% in August, extending its two-month gain to 64.4% and largely recovering some of its previous losses.

Source: LSEG

Beyond the software sector, the list also covers several market hotspots. Gold producer Newmont (NEM) rose 34.5%, while media company Paramount Skydance (PSKY) gained 37.1%.

In addition, two companies from the AI hardware sector also entered the top 10. Super Micro Computer (SMCI) rose 31.3% in August, with its Q4 FY2026 sales reaching $11.12 billion, nearly doubling from the same period last year, while full-year sales reached $39.06 billion, mainly driven by demand for AI servers and data center construction.

SanDisk (SNDK) gained 29% after announcing new long-term financial targets at its August Investor Day. SanDisk expects revenue to maintain mid-to-high double-digit growth from FY2028 to FY2030, with an adjusted gross margin remaining at around 80% and a free cash flow margin reaching approximately 50%.

The company also stated that it has signed new long-term business agreements with eight customers, covering approximately 50% of shipments for fiscal year 2027 and about two-thirds of shipments for fiscal year 2028. These agreements enhance revenue and pricing predictability while easing market concerns over cyclical volatility in the NAND flash industry.

However, a short-term rebound does not mean that previous losses have been fully recovered. As of the end of August, Salesforce, ServiceNow, and Gartner were still down 2.8%, 3.4%, and 21.5% year-to-date, respectively, while Paramount Skydance also saw a year-to-date decline of 18.6%. This indicates that the strong August performance of some stocks bears clear characteristics of an over-sold rebound.

US Stock Rally Is Gaining Earnings Support

Notably, not all of August's best-performing stocks relied on valuation expansion. Among the top 10 gainers in the S&P 500, several companies saw their forward P/E ratios decline compared to the end of 2025, indicating that earnings forecasts were upgraded faster than stock price gains.

For instance, Palantir's forward P/E dropped from 173.1x at the end of 2025 to 86.4x, Salesforce's fell from 20.2x to 15.8x, ServiceNow's decreased from 37.1x to 31.4x, and SanDisk's declined from 13.6x to 7x.

The broader S&P 500 index showed a similar trend. According to FactSet data, its weighted forward P/E ratio has declined from 22.2x at the end of 2025 to 19.7x. The combination of a rising index and falling valuations suggests that part of the U.S. stock market gains in 2026 is increasingly being driven by earnings growth rather than pure market sentiment.