Concentrated Value Investing Strategy Refined. Guy Spier's Aquamarine fund maintains its disciplined approach with a 147.5 million dollar equity portfolio heavily concentrated in high-conviction holdings. Berkshire Hathaway dominates at nearly 49 percent combined exposure, while financial franchises like American Express, Mastercard, and Moody's form the portfolio core. Recent activity shows strategic trimming across major positions and full exits from cyclical and technology names including Alphabet, reflecting Spier's shift toward ultra-high-conviction compounders with durable competitive advantages and long-term pricing power. This Buffett-inspired methodology prioritizes quality over quantity in capital allocation.