Berkshire Hathaway Inc. 13F holdings and portfolio analysis

Following Baseline means accepting the manager's disclosed sizing almost directly. Here that means high concentration in a short list of holdings: top 5 70.88%, top 10 88.27%, top 20 96.73%, with AAPL 22.60%, AXP 20.46%, BAC 10.38%, KO 10.20%, CVX 7.24%, MCO 4.60%. The baseline result is return 11.59%, alpha -1.66%, beta 1.02, Sharpe 0.65, Sortino 0.80, max drawdown -38.54%. That is the right reference case, but it is not automatically the safest case because the largest names and sector mix (Financials 42.81%, Information Technology 23.40%, Consumer Staples 14.87%, Energy 11.21%) still dominate the realized path.

The period rows show the character of the baseline. The strongest relative period was 2024-03-31 (10.08% vs SPY 4.22%, excess 5.86%, turnover 8.41%); the weakest was 2025-03-31 (-0.66% vs SPY 9.93%, excess -10.58%, turnover 3.30%). The latest rows (2025-06-30 (7.82% vs SPY 7.42%, excess 0.40%, turnover 4.67%); 2025-09-30 (5.12% vs SPY 3.13%, excess 2.00%, turnover 8.14%); 2025-12-31 (0.00% vs SPY 0.00%, excess 0.00%, turnover 4.36%)) show whether recent results are confirming or reversing the long-term profile.

Before accepting Baseline, I would inspect three things: whether AAPL 22.60%, AXP 20.46%, BAC 10.38%, KO 10.20% still have current theses, whether recent changes such as no large named moves and no large named moves indicate a shift, and whether max drawdown of -38.54% is acceptable for the user's risk budget.