The number was sitting right there on my screen — a 34% gain in eleven days. I remember leaning back in my chair, feet on the desk, thinking I'd genuinely cracked it. Not lucky. Cracked it. That specific brand of smugness is something I now recognise immediately, because it's the exact moment the wheels start coming off.

What followed was textbook overconfidence bias — the psychological trap where a string of wins, or one spectacular win, convinces you that your edge is larger than it actually is. Your position sizing balloons. Your stop-loss discipline evaporates. You stop following the process because, mate, clearly you're better than the process now.

CONCEPTPost-win euphoria feels like confidence — but it's confidence disconnected from evidence.
WARNINGTraders who abandon position sizing rules after a big win statistically blow up faster than consistent losers.
KEY IDEAYour process should feel identical after a winner as it does after a scratch trade.

The traders interviewed in Market Wizards — guys with decades of real skin in the game — repeatedly flagged this as the silent account killer. Paul Tudor Jones talked about getting humble fast after wins. Ed Seykota's entire philosophy centred on emotional consistency across outcomes. These aren't abstract ideas. They're scar tissue from experience.

Account Equity — The Post-Win Trap050100150Big WinEuphoric overtradingTime →

The fix I eventually landed on was embarrassingly simple: I treat any trade following a significant winner as a mandatory half-size trade. No exceptions. It creates a speed bump between the dopamine hit and the order entry screen. Understanding overconfidence bias in trading is one thing — building a mechanical rule that overrides it is another. The overconfidence effect is well-documented in behavioural science, and traders who understand disciplined position management consistently outperform those who size up emotionally.

Your best trade and your worst trade often share the same father — that warm, invincible feeling that you finally know something the market doesn't.

This content is for educational purposes only and does not constitute financial product advice. Past performance is not indicative of future results. Profit Logic Ltd (ACN 688 669 936) accepts no responsibility for errors or omissions in this content or anywhere on this website. Always seek advice from a licensed financial adviser before making investment decisions.