> Id assume it was independent from local data and use Yahoo.
This is what I ended up doing. However, I see a potential problem if someone is using the incremental merge capability of the Yahoo downloader. For example. Downloading a single day at the end of the trading day. The easiest way around this for now is just to download the entire stock history every time. Maybe a slightly more efficient way that keeps the merge capability is to look for any new split/dividend events within in window that’s specified. If any exists then force a full history download, otherwise do a merge.
Here are my generated results for AAPL. I can't figure out why the values are off slightly when compared to the values in git. The first dividend calculation on 20151104 results in 0.9957377 vs. 0.9957381
My equation looks like this
0.9957377 = PrevDividendAdjustment - (Dividend / (PeviousClose * PrevSplitAdjustment ));
0.9957377 = 1 - (0.52 / (122 * 1));
My Results
19980102,0.9288142,0.0357143
20000620,0.9288142,0.0357143
20050225,0.9288142,0.0714286
20120808,0.9288142,0.1428571
20121106,0.9330894,0.1428571
20130206,0.9376360,0.1428571
20130508,0.9434302,0.1428571
20130807,0.9500057,0.1428571
20131105,0.9565650,0.1428571
20140205,0.9623695,0.1428571
20140507,0.9683196,0.1428571
20140606,0.9738740,0.1428571
20140806,0.9738740,1
20141105,0.9788234,1
20150204,0.9831409,1
20150506,0.9870720,1
20150805,0.9912316,1
20151104,0.9957377,1
20501231,1,1
From GIT
19980102,0.9311149,0.0357143
20000620,0.9311149,0.0357143
20050225,0.9311149,0.0714286
20120808,0.9311149,0.142857
20121106,0.9351125,0.142857
20130206,0.9393839,0.142857
20130508,0.9448594,0.142857
20130807,0.9511153,0.142857
20131105,0.9573959,0.142857
20140205,0.9629841,0.142857
20140507,0.9687481,0.142857
20140606,0.9741588,0.142857
20140806,0.9741588,1
20141105,0.9790044,1
20150204,0.9832496,1
20150506,0.9871304,1
20150805,0.9912512,1
20151104,0.9957381,1
20501231,1.0000000,1