I am curious how things change if you used BRK earnings instead of BV.

Mainly you'd get a very jagged line, but otherwise it likely wouldn't differ that much.

If all gains were operating earnings:
* Since all earnings are retained (modest buybacks being a special case), the percentage rise in book in any interval equals the earnings in that interval.
* Singe the general trend of the book-per-share line is pretty straight in log space on this graph, we know that it is rising a fairly constant percentage in each interval.
* Therefore, earnings are rising a fairly constant percentage in every interval, once period-to-period noise is smoothed out.

That reasoning all works for operating earnings, but how do you handle the investments? If you use market value, you're at the whim of market pricing. Look through earnings would be the only way. And I'm too lazy for that these days : )

What I do have handy is the after-tax "steady things" per-share earnings figures (rails, utilities, MS&A, and cyclically adjusted underwriting profit), and investments per share. I could do a graph of those, similarly scaled to the same baseline. It will be a bit depressing, as it will really show how weak the operating earnings have been in the last few years. Depending on the multiple you assign to the operating earnings, my figures estimate that they used to account for just under half of value per share a few years ago, but now account for under 40%. Of course this is based on current earnings, which may be cyclically depressed. Or not.

Jim