Diversification
What it means
Spreading money across different assets, sectors and geographies so that no single bad outcome — one company, one industry, one country — can sink the whole portfolio.
Why it matters
It's the main reason a broad index fund is usually a safer starting point than a handful of individual stocks you've heard of.
A worked example
Hold 20 positions of equal size. One fails completely and you lose 5% of the portfolio; the remaining 19 carry on. Hold four positions and the same single failure costs 25%.
That is the whole mechanism, and it has a limit worth knowing. Most of the benefit arrives early — going from one holding to twenty removes an enormous amount of company-specific risk, while going from twenty to two hundred removes comparatively little. Past a certain point you are not reducing risk much; you are just holding more things.
What people get wrong
People count holdings instead of looking at what those holdings own. Five different funds that all track large US companies are not five bets — they are one bet purchased five times, and they will fall together.
Real diversification means holding things whose fortunes are driven by different forces: different countries, different industries, different asset types. The test is not how many line items appear in your account. It is whether you can name a scenario in which some of them go up while others go down.
How this works in Latin America
There is a concentration most people in the region carry without noticing. If you earn a salary in one country, own property there, and invest mainly in that country's market, all three depend on the same economy and the same currency. A local downturn can hit your job, your home's value and your portfolio at the same time — which is exactly the correlation diversification is supposed to break.
This is why holding some assets outside your home market matters more here than the standard advice, written for people whose home market is already globally diversified, tends to convey. The trade-off is the currency exposure noted under index funds, and it is a real trade-off rather than a free improvement.