Loss Aversion & Prospect Theory
Overview
Loss aversion, a cornerstone of Prospect Theory developed by Kahneman and Tversky, states that the psychological pain of losing is approximately twice as powerful as the pleasure of an equivalent gain. In trading, this manifests as: holding losers too long (hoping they'll come back), cutting winners too short (fear of giving back gains), and avoiding trades after recent losses.
Key Concepts
Pain of loss ≈ 2× pleasure of equivalent gain, Disposition effect: sell winners, hold losers. Endowment effect: overvaluing positions simply because you own them. Sunk cost fallacy: staying in a position because of prior investment. Reference point dependency: anchor to entry price, not current risk/reward.
Entry Signals
Recognise when you're holding a losing trade due to hope rather than analysis. Ask: 'If I had no position, would I enter here at this price?' If no, close the trade. Use predetermined stop losses to remove emotional decision-making.
Exit Signals
Pre-commit to exit levels before entering. Journal your emotional state during holds. Track whether you hold losers longer than winners statistically. Automate stop losses if you struggle to exit manually.
Best Timeframes
Ongoing self-analysis throughout every trade and trading session
Pro Tips
The most practical counter to loss aversion is pre-commitment. Set your stop loss before entry and never move it further away. Use bracket orders (OCO) to automate exits on both the winning and losing side.
More Topics in This Category
Anchoring Bias
Anchoring bias occurs when traders fixate on a specific reference point — such as their entry price, an all-time high, or a round number — and make subsequent decisions relative to that anchor rather than evaluating current market conditions objectively. This bias leads to irrational behaviour such as refusing to sell a losing position because the anchor (entry price) feels more 'real' than the current price.
Mental Accounting
Mental accounting is the cognitive bias of treating money differently based on its source, intended use, or the mental 'account' it is assigned to — even though all money is fungible. In trading, this manifests as treating profits differently from initial capital (risking 'house money' more freely), segregating portfolio performance by position rather than total, or taking excessive risk with bonus or windfall funds.
FOMO & Herding Behaviour
FOMO (Fear Of Missing Out) drives traders to enter positions impulsively because they see prices rising or because social media is buzzing about an asset. Herding behaviour — following the crowd — amplifies FOMO by creating social proof. Together, these biases cause buying at tops and chasing momentum that's already exhausted.
Hindsight Bias
Hindsight bias is the tendency to believe, after an event has occurred, that you predicted or expected the outcome all along. In trading, this manifests as reviewing charts after the fact and feeling certain that the signals were obvious, leading to overconfidence in future predictions and an underestimation of real-time uncertainty. This bias distorts trade journaling and prevents genuine learning from both wins and losses.