Thanks for your detailed reply. I need to clarify what I mean when I say "fix the quarterly statements". The quarterly statements have the dividend reinvestment details such as the total proceeds, number of shares purchased, stock price at time of purchase. This is the data I want to use to calculate the cost basis. The company (AT&T) spun-off Warner Brothers Discovery after my sale of stock. My broker sent me an adjusted basis based on the adjusted stock price. I recently learned that most historical stock prices are adjusted for corporate actions such as stock splits and spin-offs. This is done so the stock price does not show and abrupt change in price that would impact stock price trends. I am assuming that I should use the actual stock price at the time of the dividend reinvestment which shows on my quarterly statements. So this requires that I calculate the cost basis and gain from my quarterly statements not the adjusted stock price summary of gains.
