Markets Hate Assumptions. One of the quickest ways to lose money in finance is to assume the market will behave the way you expect. - Assume volatility will stay low? It spikes. - Assume correlations will hold? They break. - Assume liquidity will be there? It disappears when you need it most. Markets exist to challenge our beliefs and punish certainty. That’s why the best quants, traders, and investors build strategies that can adapt — instead of betting everything on a single assumption. Resilience > prediction. Flexibility > certainty. Risk management > confidence. Because markets don’t care what you assume. They do what they do. What’s the harshest market assumption you’ve seen break in real time?
The harshest: “liquidity will always be there.” In real time, during a flash selloff, bid-asks dry up, spreads explode, and even high-cap names gap down hard. What looks solid on models can vanish when liquidity evaporates.
Been there — assumed liquidity would save. But It didn’t. 3 lessons from that day: - Stress test extremes, not averages. - Build options (exits, hedges) before you need them. - Size positions so one surprise doesn’t end the story. Markets punish certainty. Design to survive being wrong.
Bonds and Equities negatively correlated. Only really true for 1980 to 2022 ish period.
What will happen to risk management models where assumptions and inputs are essential? And the "what if" scenario in stress testing.
"Price of crude oil must be positive"
The market is smarter than us. It is synthesizing information and strategies over multiple possible time scales and frames. Everything is already priced in. Everyone has the historical record, everyone has algorithms, everyone has backtests. The market contains a wealth of information simply to be interpreted before you even try forecasting it.
The market is always right and it has no opinion. Why trade against it?
Founder & CEO of Fortitudo Technologies | Portfolio Construction and Risk Management Author
22hGood points. For another perspective on assumptions, see also: https://www.linkedin.com/posts/antonvorobets_markets-dont-care-about-your-assumptions-activity-7318238908956258304-wCQr