€10,000 in the IBEX 35 versus €10,000 in the S&P 500, since 2009. The result: the IBEX 35 ends up at €33,412, the S&P 500 at €117,621. A brutal difference — but before jumping to conclusions, there’s a methodological detail that completely changes the comparison, and a recent twist almost nobody talks about.
Doing the comparison correctly
Both amounts are in euros, and both include reinvested dividends. This isn’t a minor detail — it’s the only honest way to compare two indexes.
The IBEX 35 you see in headlines and in most charts is a price index: it doesn’t reinvest a single dividend. And the Spanish stock market pays out, on average, around 2.4 percentage points a year in dividends. Comparing that “price” IBEX against an S&P 500 that does carry reinvested dividends wouldn’t be a fair comparison — it would flat-out be a trick that artificially inflates the gap in favor of the American index.
That’s why this exercise uses the “total return” version of both indexes — the one that reflects what a real investor would have actually pocketed, dividends included.
Why start in 2009 and not earlier?
The starting point isn’t random or convenient: 2008 data for these total return series isn’t reliable, so the exercise starts in 2009 to work with solid, verifiable figures.
The result as of 2025: a notable difference
€10,000 invested in 2009, value today (in euros, with dividends)
S&P 500 — €117,621
IBEX 35 — €33,412
The S&P 500 multiplies the capital by almost 12, while the IBEX 35 multiplies it by a bit over 3. It’s a massive difference, and it reflects what we already know: the US market has had an exceptional decade and a half, driven by the global dominance of its big tech companies.
The twist almost nobody talks about: since 2020, the IBEX wins
Here’s the most interesting part of this exercise, and the reason it’s worth looking past the headline. If instead of looking at the full period since 2009 you only look at the last few years, the result flips completely:
Starting the count in 2020, 2021, 2022, or 2023, it’s the IBEX 35 that wins the comparison against the S&P 500 — not the other way around. Spanish banks (benefiting from high interest rates) and other sectors in the index have had a much stronger recent stretch than the US market, especially versus big tech, which has suffered sharper corrections during that period.
The lesson: the time window changes everything
This exercise is a perfect example of how the period chosen to measure a return can tell completely different stories — and both can be true at the same time. “The S&P 500 has been way better than the IBEX over 16 years” and “the IBEX has been better than the S&P 500 in recent years” are both true statements — they simply measure different time windows.
This connects to something we already saw in other exercises in this series: in the Nasdaq 1999 case, the chosen entry point completely determined the path (though not the final result over the very long term). Something similar happens here: depending on which stretch you look at, the “winner” changes.
Past performance does not guarantee future returns. This exercise compares real historical data from both indexes in their total return version (with dividends), but it’s not a suggestion about which market to invest in. The goal is to show how the narrative changes depending on the time window chosen for measurement, and the importance of always comparing indexes on equal terms (same currency, same dividend treatment).
Conclusion
Sixteen years out from 2009, the S&P 500 clearly beats the IBEX 35, even when correctly comparing both indexes with reinvested dividends and in the same currency. But narrowing the window to recent years tells a different story, with the IBEX ahead. Neither reading is “the true one” — both are true, each for its own period. The key is not settling for either the “the IBEX has been losing for 16 years” headline or the “the IBEX has been winning since 2020” one in isolation, but understanding which time window you’re actually looking at every time you see a return comparison.
