Core Viewpoint - Apple remains the largest investment in Berkshire Hathaway's portfolio, but Warren Buffett's recent selling activity raises questions about the stock's future prospects [1][2]. Group 1: Buffett's Selling Activity - Buffett has sold down his stake in Apple in six of the last eight quarters, indicating a potential shift in confidence regarding the stock [2]. - Berkshire Hathaway is currently holding more cash than ever, with approximately one-third of its market cap in cash, suggesting a cautious approach to market valuations [3][6]. Group 2: Market Valuation Concerns - Buffett appears to be wary of current market valuations, as the S&P 500 trades above 30 times earnings, a level seen only a few times in the past three decades [6]. - The high cash reserves at Berkshire indicate difficulty in finding attractive investment opportunities in the current market environment [6]. Group 3: Apple’s Valuation and Growth - Apple’s price-to-sales (P/S) ratio has increased to above 10, and its price-to-earnings (P/E) ratio is nearly 40, compared to much lower ratios when Buffett first invested [8]. - Apple's revenue growth has slowed significantly, with expectations of only 8.8% growth this year and 6.2% next year, down from consistent growth rates of 10% or more from 2012 to 2022 [10]. - Despite these challenges, Apple remains a high-quality business with a strong cash flow profile, although its valuation may be perceived as excessive [11].