You can certainly lose money permanently. Liquidations, defaults, bankruptcies, etc. I've lost probably low five figures permanently on a handful of bad investments. But I've made far, far more on mostly good investments.
There's no such thing as certainty, no risk, etc in investing. You can reduce risk, but not totally eliminate it.
This is why diversification is so important. Not such a big deal if a couple of investments become worthless when you own 100 total, and most of them make you double, triple, and even quadruple digit returns here and there over the long term.
