In the 2026 edition of its annual Mind the Gap report, Morningstar found that investors have missed out on approximately 12% of aggregate total returns over the past 10 years on U.S. mutual funds and ETFs due to the timing and size of investor cash flows.

The study looked at close to 23,000 individual U.S. open-ended funds and ETFs that have existed since Jan. 1, 2016. In dollar terms, investors’ timing-related return losses amounted to about $3.8 trillion over a decade.

Overall, the average dollar invested in these funds earned 8.7% per year between Jan. 1, 2016 and Dec. 31, 2025, according to Morningstar. The funds themselves earned a total return of 9.9% per year over the same period.

“There is a gap, and it’s consistent with the…