I am, but until today thought that the adjusted prices are "forward adjusted" and represent Total Return to an investor ( and therefore adjusted prices are bigger that non-adjusted, hence my question)
As I found many vendors use "back-adjustment" (similar to continuous futures), with some deducting absolute dividend amount to adjust and some - correctly - ratio-adjust (like Quandl).
Are Zorro-supplied data ratio-adjusted?
Forward adjustment more correctly represents returns and the data do not need to be rerun with each dividend.
https://quant.stackexchange.com/questions/42445/total-returns-from-adjusted-close-prices