" Stake Decreases:
Apple Inc. (AAPL): AAPL is currently the largest 13F portfolio stake by far at ~23%. It was built between Q1 2016 and Q1 2018 at a cost-basis of ~$35 per share. The stake was decreased by 13% during Q1 2024 at prices between ~$169 and ~$195. The next quarter saw another ~49% selling at prices between ~$165 and ~$216. That was followed by a ~25% reduction during Q3 2024 at prices between ~$207 and ~$234. The last quarter also saw a ~7% trimming at prices between ~$169 and ~$225. That was followed by a ~15% reduction this quarter at prices between ~$202 and ~$258. The stock currently trades at ~$272.

Bank of America (BAC): Berkshire established this large (top three) ~10% of the portfolio position through the exercise of Bank of America warrants. The warrants had a strike price of $7.14. The cost to exercise was $5B, and it was funded using the $5B in 6% preferred stock they held. There was a ~30% stake increase in Q3 2018 at prices between $27.75 and $31.80. Q3 2024 saw ~23% selling at prices between $36.41 and $43.84. That was followed by a ~15% reduction during the next quarter at prices between $39 and $47.51. Q1 2025 also saw a ~7% trimming at prices between ~$39 and ~$48. That was followed by a ~4% trimming during the last quarter at prices between ~$33 and ~$48. This quarter also saw a ~6% trimming at prices between ~$45 and ~$53. The stock currently trades at $52.61.

Note: Berkshire’s overall cost basis is ~$14, and ownership stake is at ~7.5%."

seekingalpha.com - Tracking warren buffetts berkshire hathaway portfolio q3 update