Why are stock and mutual fund return figures inaccurate?

I realize they are downloaded....that does not explain the difference. As an example, Quicken statement says VTSAX (Vanguard Total Stock Market Index) returned 22.3% (3 Yr) and 22.3% (5 Yr). Morningstar report says 18.8% (3 Yr) and 17.98% (5 Yr). Quicken statement says AGTHX (Growth Fund America) returned 32.3% (3 Yr) and 32.3% (5 Yr). Morningstar report says 20.26% (3 Yr) and 20.76% (5 Yr). These are totally inconsistent. None of the 3 and 5 year number on my Quicken statement are accurate.

You may be on to something with your comment about duration of ownership. I started using Quicken in about 1999, but Quicken for Windows. Finally in November of 2019 I converted to Quicken for the Mac. Ironically, I put off the conversion for years because I always heard that the portfolio management part of the Mac program was far inferior to the Windows version. I have found that very true. One item different is the annual returns. The Mac version uses Morningstar data (I believe) only current to the end of the prior month….the data is old. (I am not certain if this is true or not. Perhaps Quicken calculates the data?)

Please review the attached photos. You will see my issues in the 3 and 5 year return data. When I converted from Windows I automatically downloaded all the data from Windows to the Mac Quicken version. Perhaps the software is unable to properly handle the time period thing. Maybe the Mac version cannot treat the stock purchase dates correctly due to the conversion from Windows? It is a shame it is so limited in reports and analysis information. The Windows version was so much better at portfolio management.

Thanks for looking into this. If you have any more insight…please share it.