No. of Recommendations: 10
5 years isn't long enough to derive any meaningful conclusions.
Here is a site that has P/B back to 2004.
https://www.financecharts.com/stocks/BRK.B/value/p...You said you derived it using SEC filings for more than 5 years, so why didn't you do more than 5?
The time between datapoints is not regular, which would make analyzing it a bit painful. Which is why I haven't done it yet.*
BTW, you don't really need Python to scrape price history from Yahoo financial. Cut/paste works just fine.
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[*] Duh, I just realized it would be easy. In Excel, just have another table of historical prices and do a table look up for each P/B datapoint. **smacks forehead**