比线性外推更危险的事儿

Core Viewpoint - The article emphasizes the dangers of "linear extrapolation" in investment decisions, highlighting that past performance does not guarantee future results and that many investors fall into the trap of assuming trends will continue indefinitely [3][7]. Group 1: Historical Context and Examples - The author reflects on the decline of traditional media, particularly print, which was once thriving but has since struggled due to the rise of mobile internet [4]. - Examples of companies that failed to adapt include Nokia and BlackBerry, which were once leaders in mobile technology but were overtaken by the advent of smartphones [5]. - The article also mentions the decline of major supermarket chains like Carrefour and Emart, which have faced challenges from e-commerce and delivery services [6]. Group 2: Market Analysis - The S&P 500 index has shown a long-term upward trend with an annualized return of 9.42% over nearly 40 years, indicating its resilience despite short-term fluctuations [8]. - However, the current S&P 500 index is near the upper bound of a 1.5 standard deviation confidence interval, suggesting potential risks of regression to the mean, especially if a significant market correction occurs [10]. - A regression analysis of the A-share market indicates a 7.69% annualized return over the past 25 years, which, while lower than the S&P 500, is still a reasonable return [12]. Group 3: Current Market Position - The current position of the A-share market is slightly below the fitted regression line, indicating a potentially lower risk environment for investors at this time [15]. - The volatility of the A-share market is noted, with the confidence interval being wide and capable of experiencing significant fluctuations [17].