Aquamarine Capital Management, LLC 13F holdings and portfolio analysis

Directly following the baseline means accepting an extremely top-heavy financials portfolio. In the baseline artifact, the top 5 holdings are 100% of assets: AXP 27.04%, MA 25.68%, BRK.A 25.47%, MCO 15.5%, and DJCO 6.31%. Sector exposure is 93.69% Financials and 6.31% Information Technology. That concentration helped produce 16.58% annualizedReturn and 336.42% totalReturn, but it also left beta at 1.05 and maxDrawdown at -37.91, so the investor is effectively buying a handful of high-conviction financial franchise names with substantial single-sector and single-name risk.

Three recent baseline periods stand out. First, 2025-06-30 delivered 18.54% optimizedReturn versus 4.2% benchmarkReturn, a +14.33 pt excess return with only 5.85 turnover, showing how the concentrated structure can add large upside when holdings work. Second, 2023-12-31 returned 13.41% versus 4.96% for SPY, a +8.45 pt excess return with 7.97 turnover, another strong payoff from concentration. The trade-off shows up in weaker quarters like 2024-03-31, when baseline returned -2.44% against SPY’s 2.31% for a -4.75 pt excess return, and 2025-03-31, when it lagged by -4.78 pts. Those swings fit the overall profile of 16.58% annualized return but a -37.91% max drawdown.

A user should inspect concentration path, sector dependency, and lag risk before accepting the baseline. Concentration is already absolute in the baseline artifact, with top5 at 100% and Financials at 93.69%, so the next question is whether that concentration has been stable or rising. Users should also inspect periodPerformance because strong gains came with uneven timing, including +14.33 pts excess in 2025-06-30 but -4.75 pts in 2024-03-31. Finally, the risk notes matter: the backtest uses delayed filing implementation and still posted -37.91% maxDrawdown and 302 trades with totalEstimatedCost 1.206, so copying it is not the same as owning the manager’s real-time book.