These Were the 5 Top-Performing Stocks in the S&P 500 in August 2025

In August, five S&P 500 stocks—Albemarle, UnitedHealth Group, Intel, Humana, and Idexx Laboratories—each surged over 20% against the S&P 500's 2% gain, driven by diverse catalysts including competitor supply disruptions for Albemarle, strategic investments in UnitedHealth (Berkshire Hathaway) and Intel (SoftBank, US government), analyst upgrades for Humana, and strong Q2 earnings for Idexx. While acknowledging short-term market volatility, the analysis identifies Idexx Laboratories as a favored long-term investment, citing its consistent growth, robust gross margins, and strong tailwinds in the pet healthcare sector.

Analysis

Five S&P 500 constituents—Albemarle (ALB), UnitedHealth Group (UNH), Intel (INTC), Humana (HUM), and Idexx Laboratories (IDXX)—significantly outperformed in August, each delivering returns between 21% and 25% against the S&P 500's 2% gain. The drivers for this performance were disparate and company-specific. Albemarle's rise was attributed to speculation of higher lithium prices after a key competitor halted production. UnitedHealth, despite facing headwinds including higher costs and a DOJ investigation, saw its stock rebound from five-year lows following the disclosure of a $1.6 billion investment by Berkshire Hathaway. Intel received substantial capital infusions totaling $10.9 billion from SoftBank and the U.S. government to bolster its semiconductor production. Humana's stock price increased steadily on the back of positive analyst outlook upgrades following its late-July earnings. Idexx Laboratories reported better-than-expected Q2 2025 financial results on August 4, prompting management to raise its full-year guidance. The analysis favors Idexx for long-term investment, citing durable secular tailwinds in pet healthcare, a management target of 10%+ growth, and consistently increasing gross margins over two decades, which indicates a strong competitive moat.

Key Decisions for Investors

• Investors could consider Idexx Laboratories for long-term growth, given its strong Q2 earnings beat, raised guidance, and durable tailwinds in the pet healthcare sector, which are supported by accelerating growth and robust gross margins.
• For those with a higher risk tolerance, Intel's significant financial backing from both private and government sources presents a potential turnaround opportunity, though the company's history of lackluster results warrants caution.
• The recent surge in Albemarle's stock is tied to a competitor's operational halt rather than its own fundamental improvements, suggesting investors should be cautious about the sustainability of this price appreciation.
• Holders of UnitedHealth and Humana should monitor the political and consumer sentiment landscape in the healthcare sector, which the analysis identifies as a significant, albeit hard-to-predict, risk factor despite recent positive performance catalysts.