Building a portfolio

If 80% of your money sits in one company, one bad earnings call takes the whole portfolio with it. Spread across companies, sectors and asset types and no single storm gets everything.

It's called the only free lunch in finance because it's the rare move that lowers risk without a matching cut to expected return.

Diversification softens blows. It never cancels them — everything can fall together, and sometimes does.

Ten different tech stocks is not diversification. They rise together and — the part that matters — they fall together, because they answer to the same rates, the same cycle and the same story.

Correlation measures how much two things move in step. Real spread means holding things that genuinely don't: shares and bonds, different regions, different currencies.

Count what your holdings have in common, not how many there are.

A structure you'll see constantly: a boring diversified core doing most of the work — typically broad ETFs — plus small satellite positions for your actual convictions.

The core compounds quietly. The satellites keep it interesting, and cap the damage when a conviction turns out to be a phase.

It lets you be wrong about individual calls without being wrong about your whole plan.

How much you put in matters more than what you put it in. A brilliant pick at 2% barely moves your year; a mediocre one at 50% defines it.

The useful test before any spicy position: if this goes to zero, what happens to my portfolio — and would I still be able to sleep, and hold the rest?

Losses are asymmetric, which is the maths people learn the expensive way. Down 50% needs +100% just to get back to even.

Size for survival. You can't compound from a position you panic-sold.

Compounding is returns earning returns. It's unremarkable for years and then does almost all of its work at the end — which is why starting early beats starting big.

It's also why jumping in and out is expensive: a handful of the best days carry a huge share of long-run returns, and they cluster right next to the worst ones. Miss a few while waiting for calm and the whole curve flattens.

Your savings rate and your patience usually matter more than your pick quality.

Every fee is a permanent deduction from the compounding curve. A fund charging 1.5% a year versus one charging 0.2% doesn't cost you 1.3% — it costs you 1.3% every year, plus all the growth that money would have made.

Trading costs work the same way, which is why frequent churn is such a reliable way to underperform the thing you were trying to beat.

Returns are uncertain. Costs are guaranteed. Guess which one deserves more of your attention.

Verified means the numbers came straight from a connected brokerage or exchange, read-only — they can't be typed in. Self-reported means someone entered them by hand, and it's always labelled as such.

Public and friends views show percentages, multiples and risk — never euro amounts. Nobody needs your balance to judge your calls, and hiding it keeps the flexing about skill rather than salary.

Everything in the feed is an opinion, labelled as one. What fits your life — your income, your horizon, your nerves — is yours to decide.

Receipts and risk, so you can judge for yourself. Never advice.