The current peak book was recorded in Q1 2022. We've just closed Q1 2023. The economy has grown a bit over the last year, and inflation has been significant. Buffett has made numerous apparently astute investments. So we might expect the business value to have grown in real terms and even more in nominal terms.

At the same time, as AdrianC posted in response to my thread on this a week ago, Apple is down a bit, and Bank of America is WAY down, so, actual book value of stocks held is likely down significantly, and I expect reported book value at the end of Q1 will not be a new peak.

Overall, I'd expect that the intrinsic value of the business has been chugging along nicely even while a declining stock market has dropped the book value, so the current peak price/book of 1.3 (using current price of 298.92.) is a better value than it was last July and August, for instance.

Book value at the end of the 4th quarter:
equivalent Class A common stock basis, there were 1,459,733 shares outstanding as of December 31, 2022
Berkshire Hathaway shareholders' equity 472,360 million.
Book value per A share: $323,593
Book value per B share: $215.73