Subject: Re: On Topic (really :): A Berkshire Hathaway question
Here's a fresh table.

Average one year forward REAL returns, based on ratio of price to peak-to-date book per share on purchase date.
Ending dates smoothed a bit.

First column is the average price-to-peak-book in that bucket. Each bucket is 1/20th of the observation start dates.
Second column is the average real one year return starting with a P/peakB in that bucket.
Third column is my smoothing of that data.
(I did a linear fit, and a cubic fit, and averaged those two results)

P/Peak    Obser     Model
1.075     34.6%     30.1%
1.165     22.2%     20.6%
1.204     19.1%     17.5%
1.250     15.4%     14.5%
1.295     10.5%     12.1%
1.323      4.6%     10.8%
1.343      5.5%     10.0%
1.359      9.7%      9.4%
1.376      8.5%      8.8%
1.392      5.5%      8.2%
1.412      4.5%      7.6%
1.438      5.7%      6.9%
1.461      6.8%      6.2%
1.483      5.3%      5.6%
1.509      7.7%      4.9%
1.537      8.1%      4.0%
1.579      3.5%      2.7%
1.638      4.0%      0.4%
1.693     -2.2%     -2.4%
1.808    -12.0%    -10.9%

1.303               11.7%  today

Last row is today with price at precisely $300 / $450000.
So, if the next year resembles the average stretch in the last ~20 years, one would expect a one year return of inflation + 11.7% in the next year.
That will be wrong, of course, but the idea is that it's a 50/50 shot whether it's too high or too low.

BUT...
You should probably knock about 4% off that expectation because the P/B multiples were so much higher 2003-2007 than in recent years.
If I look only at my sundry models starting with data from 2008, the implied expectations are more like inflation + 7.7%. Still not bad.
The rate of growth in value per share has been remarkably constant...it's the market multiples that make the difference.

Jim