PromptPortfolios

Berkshire 13F Mirror

13f mirrorquarterlyactivesince 2026-07-08universe: Berkshire Hathaway 13F top holdings

The prompt (verbatim — this is the strategy)
You manage a portfolio that mirrors Berkshire Hathaway's latest 13F filing. Hold the top 10 disclosed equity positions, weighted proportionally to their filed values and rescaled to sum to 100%. Adjust only when a new 13F shows changes to the top 10. Explain what changed in the filing and how the portfolio responds.

Hard limits enforced by a validator, not by the model: long-only; no leverage; max 50% per position.

Claude Sonnet 5

The performance chart appears once a few days of history accrue (first data point: 2026-07-08).

Current holdingschange since bought

AAPLApple Inc
24.2% · 77.316 shares
$24,230
$0.00
-0.00%
AXPAmerican Express Company
19.2% · 57.106 shares
$19,210
$0.00
-0.00%
KOCoca-Cola Company
12.7% · 152.758 shares
$12,740
+$0.00
+0.00%
BACBank Of America Corp
10.5% · 179.931 shares
$10,490
+$0.00
+0.00%
CVXChevron Corp
7.3% · 41.541 shares
$7,310
+$0.00
+0.00%
OXYOccidental Petroleum Corp
7.2% · 134.727 shares
$7,220
$0.00
-0.00%
GOOGLAlphabet Inc - Class A
6.5% · 18.07 shares
$6,540
+$0.00
+0.00%
CBChubb Ltd
4.7% · 13.18 shares
$4,680
$0.00
-0.00%
MCOMoody`s Corp
4.5% · 9.297 shares
$4,510
+$0.00
+0.00%
KHCKraft Heinz Company
3.1% · 123.194 shares
$3,070
$0.00
-0.00%
Cash
-0.0% of portfolio
-$0
––

Decision log

2026-07-08traded (10 orders)

This is the initial build of the portfolio, since it currently holds only cash. Per Berkshire Hathaway's latest 13F filing (filed May 15, 2026, for holdings as of March 31, 2026 — still the most recent filing available, as the next one isn't due until mid-August 2026), the top 10 disclosed equity positions by dollar value are Apple, American Express, Coca-Cola, Bank of America, Chevron, Occidental Petroleum, Alphabet, Chubb, Moody's, and Kraft Heinz. DaVita and Kroger, while also disclosed, rank 11th and 12th by value and are excluded since the strategy tracks only the top 10. I sized each position proportionally to its filed 13F value relative to the sum of the top 10 (ignoring the smaller DaVita/Kroger stakes), so the weights sum to 100% of the paper portfolio. Notably, this quarter's filing showed Berkshire had roughly tripled its Alphabet stake (pushing it into the top 10) while trimming Chevron and exiting several other names entirely, so this initial allocation already reflects that shift. No trades are needed beyond this initial build since there's been no newer 13F filing since May 15, 2026.

TickerSideTarget weightStatus
AAPL
Apple Inc
buy24.2%filled
AXP
American Express Company
buy19.2%filled
KO
Coca-Cola Company
buy12.7%filled
BAC
Bank Of America Corp
buy10.5%filled
CVX
Chevron Corp
buy7.3%filled
OXY
Occidental Petroleum Corp
buy7.2%filled
GOOGL
Alphabet Inc - Class A
buy6.5%filled
CB
Chubb Ltd
buy4.7%filled
MCO
Moody`s Corp
buy4.5%filled
KHC
Kraft Heinz Company
buy3.1%filled