如何合理止损？

Core Viewpoint - The article discusses the controversial topic of "stop-loss" strategies in investing, highlighting a recent paper by Nassim Nicholas Taleb that quantifies the effects of stop-loss through Monte Carlo simulations, suggesting that stop-loss may lead to more losses rather than preventing them [1][2]. Group 1: Key Findings from the Paper - The paper presents a graph showing that without stop-loss, the return distribution follows a normal distribution, peaking at slight losses, while implementing a 10% stop-loss increases the probability of positive returns but also creates a peak of losses at the stop-loss threshold, termed "Dirac Mass" [5]. - In a market with an annualized volatility of 20-25%, there is a 50% probability of hitting the 10% stop-loss, which is higher than most investors expect. For A-shares, particularly small-cap and tech stocks, the probability can reach 85% [5]. - Stop-loss is likened to insurance against catastrophic losses but alters the probability distribution of returns, leading to several recommendations: fixed stop-loss percentages below 20% are ineffective against random noise, and stop-loss levels should consider market volatility [6][7]. Group 2: Practical Issues with Stop-Loss - The first issue is how to minimize the damage caused by stop-loss, which can be seen as an expensive insurance policy that does not save poorly thought-out investments [11]. - The second issue involves trading in a non-trending, volatile market, where even experienced traders can incur significant losses due to psychological pressures and frequent stop-loss triggers [12]. - The third issue is the impact of high leverage on stop-loss effectiveness, where the probability of permanent losses increases, making stop-loss strategies more critical but also more damaging [13]. Group 3: Perspectives on Stop-Loss for Different Investor Types - Value investors, like Warren Buffett, generally oppose stop-loss strategies, believing that price declines can represent buying opportunities rather than triggers for selling [17]. - Retail investors may benefit from stop-loss strategies due to their ability to quickly adjust positions, but they often struggle with emotional trading and information asymmetry, leading to frequent losses [20][21]. - The psychological barrier of not wanting to realize losses can be addressed through techniques like "mental stop-loss," which encourages investors to reassess their positions without the emotional burden of past decisions [26].