rrr12345:
As an example, here is the list of IV estimates that I found for Dec 31, 2012. The document shows a histogram of the estimates as well as a table showing the sources. BV as of Dec 31, 2012 was $114,214, so the average IV estimate of $175K corresponded to 1.53x Dec 31 BV.

So there like a trilobite fossil is a record from the past of what people thought the IV of BRK.A was at EOY2012.

We can find out in retrospect if they were right. Suppose the plan was to hold that share until EOY2025 when it could then be sold for $754,800. Suppose we agree with mungofitch that the proper discount rate for finding IV is 6.5% per year plus inflation. Then we can calculate the IV of that BRK-A share in 2012 dollars:

$754,800 * 1.065^-13 / 1.402 = $237,432, which would have been 2.1x Dec 31,2012 Book Value.

To be clear, 1.065^-13 discounts the price back 13 years ago to the 2012EOY date and 1.402 is the value of an EOY2012 US$1 in EOY2025 US Dollars.

So the people back in early 2013 underestimated the IV by quite a lot, and the "true" relationship of IV to book value back then was 2.1x book value.

What might one take away from this?

1) The actual cash flows that matter to investors are the date and price they bought the share at and the date and price they sold, (or will sall) the share at.
2) Since BRK.A has been appreciating, on average, at a CAGR which is higher than 6.5% real, the true IVs from back 10, 20, 30, 40 years ago are very significantly higher than both the then prevailing share prices and the then prevailing book values.
3) So whatever this Price/Book ratio of 1.4 that sort of fits the stock price to the book value in the last 10 or 20 years, it is generally speaking a significant underestimate of the discount with which the price and the book were offered in the market back then.

I have looked at actual discounts of the stock price for decades prior to a planned EOY2025 stock sale. A sample of discounts were:

	Buying BRK
	Cost of 
	$1 of IV
EOY	in cents
1980	3.8%
1990	21.9%
2000	81.8%
2010	61.6%
2020	77.7%
2025	100.0%

Which is to say at the price BRK.A was selling for in 1980, you were able to buy $1 of stock IV for only 3.8 cents! By 1990 it would cost you 22 cents to buy a $1 worth of stock IV. You continued to get the stock at a discount. And because these are all calculated with the plan to sell the share at EOY2025, there is no discount in buying a share of stock at EOY2025 and then selling it back at the same price.