Investors chasing hot returns in a surging stock market may find their diversification efforts backfiring. Hot stock markets often see broad upward trends where most sectors and companies move in tandem, significantly reducing the risk-mitigating benefits of spreading investments across different assets. This phenomenon occurs because investor sentiment becomes overwhelmingly positive, driving prices up uniformly rather than allowing defensive positions or uncorrelated assets to provide ballast. Diversification loses its protective value when markets are dominated by a single powerful trend, leaving portfolios vulnerable to sharp reversals if that trend falters. The Wall Street Journal warns that relying solely on a rising market for safety can be a critical miscalculation for long-term wealth preservation.