Lesson Learned: Over-leveraging on a 'sure thing' Polymarket

Looking back at the 2020 election markets on Polymarket, my biggest screw-up wasn't being wrong on a particular outcome, but how I sized into what I thought was an absolute lock. Specifically, the 'Who will win the US Presidential Election?' market. I was so convinced by the polling data and certain narrative points that I threw an outsized portion of my available capital into one side, completely ignoring the implied volatility and tail risk that Polymarket, like any market, always carries.

I essentially treated a probabilistic outcome as a certainty. When the initial results started to swing unexpectedly, my position was underwater significantly. My mistake wasn't just the directional call, but the complete disregard for risk management and position sizing based on my confidence rather than market reality. It wasn't revenge trading, just pure, unadulterated overconfidence leading to over-leveraging on a single event. Ended up having to rebalance at a loss to free up capital for other positions that were actually more balanced risk-reward. Taught me to always size for the worst-case scenario, even if the best-case feels imminent.