Navigating Market Swings: The Emotional Rollercoaster of Stock Investing

Giverny Capital's Second Quarter 2026 Investment Review

Giverny Capital Asset Management, an investment firm, recently released its investor letter for the second quarter of 2026. This letter provided insights into the firm's model portfolio performance, which recorded a 13.70% return for the quarter, slightly trailing the S&P 500's 15.20% gain. Year-to-date, the portfolio saw a 5.89% increase, while the S&P 500 climbed by 10.21%. The letter underscored the enduring relationship between stock appreciation and corporate earnings growth, echoing Benjamin Graham's analogy of the market as a 'voting machine' in the short term and a 'weighing machine' over the long haul. Despite the overall market's positive first half, a significant number of stocks experienced declines, highlighting market inefficiencies. The firm noted that companies with robust earnings that can leverage AI technologies are well-positioned to maintain their competitive advantages. Current market dynamics show a strong inclination towards momentum-driven investments, with major technology companies capitalizing on investor optimism amidst concerns of an AI valuation bubble. While these tech giants demonstrate impressive profit margins, their reliance on speculative, high-risk ventures raises questions about long-term sustainability. Giverny Capital recommends a diversified investment approach, including both established industry leaders and innovative emerging technology firms.

AAON's Volatile Stock Performance and Market Cap

In its Q2 2026 letter, Giverny Capital Asset Management specifically highlighted AAON, Inc. (NASDAQ:AAON). This company specializes in the design and production of advanced air conditioning and heating equipment. As of July 21, 2026, AAON's shares were trading at $105.61, giving the company a market capitalization of $8.65 billion. Over the preceding month, AAON experienced a downturn, with a return of -19.75%. However, looking back over the past 52 weeks, the company's shares demonstrated a strong performance, appreciating by 34.11%.

The Dynamics of Investor Sentiment and AAON's Stock Movement

Giverny Capital Asset Management offered a poignant observation regarding AAON, Inc.'s stock performance, noting how the interplay between investor excitement and apprehension can trigger rapid trading decisions. The firm recalled a particular day in May when AAON reported strong earnings, leading to an immediate 31% surge in its stock price. This significant jump was attributed to AAON's successful business unit focused on cooling systems for data centers, an area experiencing high demand. However, the letter also provided a 'reality check,' mentioning that AAON's stock subsequently relinquished a substantial portion of its single-day gains, illustrating the swift and often unpredictable nature of market reactions influenced by emotional trading.

Comparative Investment Opportunities and AI Stock Landscape

Despite recognizing AAON, Inc.'s investment potential, it is not listed among the 40 most favored stocks by hedge funds heading into 2026, according to Giverny Capital's data. The firm's records indicate that 30 hedge fund portfolios held AAON shares at the close of the first quarter, a decrease from 36 in the prior quarter. While acknowledging AAON's merits, Giverny Capital believes that certain AI-focused stocks currently present more attractive upside potential coupled with reduced downside risks. For investors seeking highly undervalued AI opportunities that could also benefit from evolving trade policies and the trend towards domestic manufacturing, the firm suggests exploring its specialized report on leading short-term AI investment prospects.