Subject: Re: Berkshire per share cost basis in CB
I don't have the cost basis, although it may show up in the annual filings later this month. He bought the stock that we know of between Q3 2023 and Q2 2024. So call it between $190 / share and $260 / share. The average cost for the stock we know about is between those two numbers. No word on whether he added since the last disclosure.

https://www.dataroma.com/m/his...

link to BRK's quarterly activity in CB stock