Your ROI is total ROI of perhaps many purchases regardless of the dates they were bought. I would like to see the ROI of all purchases of a holding on a yearly basis to judge whether the holding is a good one. For example, if I have 5 positions of a stock bought over 4 years and your system says the ROI is 40%, I have no way of knowing it it has been a good investment. I would have to examine each purchase and somehow mathematically figure out my ROI per year. Such info would be very useful as a column in the portfolio.