We've had some stock in one company since the early 1990s. We had the dividends reinvested in the stock each time they were paid, so the records show we bought fractional shares from time to time over the years.
Recently we sold a chunk of that stock, so I'm trying to figure out the cost basis for taxes. The broker listed the date each share or fraction was acquired, but no corresponding purchase price.
I've pulled down daily historical records for this stock, but those show the opening, high, low, and adjusted close figures for each day. Since I don't know when during the day the stocks were purchased, can I use the daily average between the high and low (or adjusted close, if it's higher or lower than either of those figures)? I no longer have individual records of those incremental purchases.