How do I get a handle on correlations and tail risk in a portfolio?

You can manage the risk you can see. What still slips past you is how positions move together, and the rare, brutal event that hits everything at once. That is honest to admit, because these are the hardest parts. Most people who claim to have them fully mastered are fooling themselves.\nHere is a way to think about it. Correlation is just the question, what else breaks when this breaks? Tail risk is the question, what happens on the worst day I can imagine, and the one worse than that? You do not need perfect math to start. You need the habit of always asking those two questions about every position, not just its own risk in isolation.\nSo take your current book and run one exercise. Pick a single bad scenario, a real one, and trace it through every position you hold. What moves, and how far, all at once? Do that by hand, this week. You will learn more about your true exposure from one honest stress test than from a month of staring at each position alone.