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Pete took an action item to do research on information we need to retain with respect to adjusted prices from a historical perspective. See https://github.com/joshuaulrich/quantmod/issues/174, for example.
From JG: The adjusted closing price amends a stock's closing price to reflect that stock's value after accounting for any corporate actions. The closing price is the raw price, which is just the cash value of the last transacted price before the market closes.
Regardless of what we decide to retain, we should confirm what historical prices published by an exchange actually are, whether they are adjusted to address stock splits only or stock splits plus dividends, etc.
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