Ten years feels long enough to understand an investment. If an ETF has compounded at 10% or 15% a year for a decade, calling it a strong investment does not feel like performance chasing. It feels like reading the evidence.
But a trailing return is not a permanent property of a fund. It is a description of one starting price, one ending price, and the economic regime between them. Sometimes the next ten years look so different that the first decade seems to have described another investment entirely.
Three Canadian sector ETFs make the point unusually cleanly. They all use the same two periods: December 2001 to December 2011, followed immediately by December 2011 to December 2021.
Three Canadian ETFs across two decades
Annualized total returns in Canadian dollars. Distributions are reflected in adjusted prices.
| ETF / exposure | Dec. 2001–Dec. 2011 | Dec. 2011–Dec. 2021 | What changed |
|---|---|---|---|
| XEG.TOCanadian energy producers | +10.78% | −2.29% | Strong → weak |
| XGD.TOGlobal gold producers | +10.11% | −1.44% | Strong → weak |
| XIT.TOCanadian technology companies | −4.92% | +23.05% | Weak → strong |
CAGR from monthly Yahoo Finance adjusted-close data. These are historical measurements, not fund-return forecasts.
The same ten years can make opposite arguments
At the end of 2011, the historical case looked flattering for energy and gold miners. XEG had compounded at 10.78% a year for ten years and XGD at 10.11%. Technology had done the opposite: XIT had lost 4.92% a year.
Then the leadership reversed. Over the next ten years, XEG lost 2.29% annually and XGD lost 1.44%, while XIT compounded at 23.05%.
This is not a claim that investors should have recognized a guaranteed rotation in 2011. That would replace one kind of hindsight with another. The useful point is narrower: the first decade contained a great deal of information about what had happened, but much less information about what would happen next.
Strong decade, weak decade
The pattern is not limited to one Canadian sector cycle. Here are several other ETFs whose second ten-year period was dramatically weaker than the first.
When a strong decade did not continue
Annualized total returns in each ETF’s listing currency.
| ETF / exposure | First 10 years | Next 10 years | Pattern |
|---|---|---|---|
| EWZBrazilian equities | 2000–2010+20.14% | 2010–2020−4.62% | Strong → weak |
| ILFLatin American equities | 2002–2012+22.00% | 2012–2022−2.46% | Strong → weak |
| IBBBiotechnology companies | 2004–2014+15.13% | 2014–2024+2.96% | Strong → subdued |
| EWAAustralian equities | 1997–2007+15.81% | 2007–2017+2.56% | Strong → subdued |
Weak decade, strong decade
The reverse also appears. A decade that looked like a reason to abandon an exposure was sometimes followed by a decade that made the earlier result feel unrecognizable.
When a weak decade was followed by a strong one
Annualized total returns in US dollars.
| ETF / exposure | First 10 years | Next 10 years | Pattern |
|---|---|---|---|
| QQQNasdaq-100 companies | 1999–2009−6.42% | 2009–2019+17.83% | Weak → strong |
| SOXXSemiconductor companies | 2001–2011−2.55% | 2011–2021+28.64% | Weak → strong |
| IGVSoftware and technology companies | 2001–2011+1.84% | 2011–2021+22.43% | Subdued → strong |
| XLYUS consumer-discretionary companies | 1999–2009+0.61% | 2009–2019+17.15% | Subdued → strong |
What changed?
There is no single explanation shared by every row. Commodity cycles matter for energy producers and miners. Starting valuations matter for technology. Interest rates, currencies, regulation and regional growth all affect different funds differently. The companies inside an index also change over time.
The common thread is that a return belongs to a period. A sector can enjoy favourable economics while becoming increasingly expensive. Another can spend years disappointing investors while its starting valuation, competitive position or underlying businesses quietly change. The trailing number records all of that in one tidy percentage, but it cannot tell us which parts will still be present in the next period.
This is not a contrarian strategy
It would be easy to look at these tables and invent a rule: sell whatever had a strong decade and buy whatever had a weak one. The data does not support that conclusion. These examples were selected because the reversal happened. Plenty of funds continued performing well, remained weak, closed, merged or never accumulated enough history to appear here at all.
That hindsight matters. The tables illustrate that leadership can reverse; they do not estimate the probability of a reversal. A weak decade is not stored-up future performance, and a strong decade is not an expiration date.
For me, the practical use is simpler. When someone quotes a fund’s ten-year return as though it were an expected return, I mentally add two words: ending today. Move the starting date, the ending date or the economic regime and the number may tell a very different story.
Ten years is long, but it is still one period
A decade is useful evidence. It can show how an investment behaved through recessions, booms, rate changes and market shocks. It is much more informative than a good quarter or a lucky year. But it is not long enough to turn an historical outcome into a permanent characteristic.
This is one reason I prefer diversified portfolios to choosing whichever sector, country or theme currently owns the best-looking track record. Diversification does not identify the next leader. It reduces how much your plan depends on identifying it correctly.
If you want to examine another ticker or choose your own dates, the Portfolio Backtest Lab shows total return, volatility and drawdowns over a selected period. The ETF Comparison Tool places several ETFs on the same shared window.
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