In my case, I originally bought 1000 shares in 2012. I adjusted the original basis ($10,000) by the amount of ROC received from 2012 through 2019. Prior to the merger the adjusted basis was $4,924.78. The merger paid $5.33 per share for a total of $5,333.00. Therefore, I believe I need to report a gain of $405.22 ($5,333.00-$4,924.78).
After countless hours of research, because of your explanation, I think I may finally understand it! Many thanks. If by chance I misunderstood your explanation, please let me know. Before this research I did not realize I needed to adjust the basis by ROC received. BTW, for anyone in a similar situation, the easiest way to determine the ROC (aka nondividend distributions) received each year is to look at each 1099-DIV received each year since your original purchase. Luckily, the commodity I was dealing with had all of them readily available for my account on their website.
