For background my Quicken database is old. We've been using it since the early 90's. The age of the database may contribute to this bug not being discussed previously. I'm currently running the Windows Beta version of Quicken since 4th qtr 2025, but this calculation error has plagued me for years. I was hoping that one day an update would address this old problem. I only discovered the fix this past weekend. And, Yes, my IRR calculation does include unrealized gains already, so that was not a fix.
The Bug is the Beginning and Ending Mkt Val (in the Investment Performance Report table) did not match the values for a stock on those dates found in the Investing>Portfolio table.
The Fix is to make note of all stock splits for each ticker. Delete the stock split in an account, and re-enter it from your notes. I tried to slightly change the stock split then change it back, but that did not fix the calculation. Only deleting and re-entering the split fixes the IRR calculation to the correct Beginning/Ending Mkt Values.
Many stocks were 50 to 80% too low for Mkt Value. Some stocks were even showing an impossible negative Mkt Value. No stock can possibly have negative value.
Finally one stock let me find a fix since there were no dividends, sells, or buys in the time period. It only had stock splits. I had to delete many other stock splits as far back as the mid 90s. I did not bother to determine which time period of stock splits were the source of the problem.
