Discrepancy between ETFs performance and benchmark index

External question — Personal Finance Stack Exchange Author: Sekory Original post: https://money.stackexchange.com/questions/152430 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I am interested in MSCI World Index and was comparing several ETFs. I can understand that performance of ETF itself can be slightly different but how is possible that there is difference in benchmark performance? Lyxor Core MSCI World (DR) UCITS ETF - Acc has benchmark performance for 2019 27.7% Xtrackers MSCI World UCITS ETF has benchmark performance for 2019 28.6%. There is more: Invesco MSCI World UCITS ETF has performance 31.2% with benchmark performance 31.1% in 2021. Xtrackers MSCI World UCITS ETF (and others are similar) has only performance 21.9% with benchmark performance 21.8% in 2021. How can I even find benchmark index? I suppose it should be net MSCI World Index (USD) . Only way I can explain Invesco 2021 performance is that they decided to show the performance in EUR instead of USD. But how I can trust these documents then? And how ETF with size of 3 billion dollars cannot get even basic KIID required by law right? I am not sure even how I should check performance myself should it be 1/1 (or first trading day) to 31/12 or 1/1 to 1/1 and open or close price? TL;DR: How is it possible for ETF benchmark performance to be different? How can performance differ by 10% in a year? Are KIIDs reliable source of information?

External answer — Personal Finance Stack Exchange Author: Manziel Original post: https://money.stackexchange.com/a/152436 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. How is it possible for ETF benchmark performance to be different? There is more than one index that is called MSCI World. One big difference is the treatment of dividends, one can either completely ignore them, completely reinvest them (total return index) or something in the middle as dividends typically will be taxed (e.g. net total return). The other big difference is currency. Recently the exchange rate between euro and USD had rather big changes. How can performance differ by 10% in a year? My suspect here would be currency. Dividends for a general index are more in the magnitude of 2%, so they cannot account for 10% change Are KIIDs reliable source of information? KIIDs are legally required investor documentation. Therefore incorrect information is not acceptable. Of course, they are made by humans and whenever there are humans involved, there will be an error sooner or later.