The Wall Street Journal reported on August 30 that the once-popular "momentum trading" strategy (buying rising stocks and shorting falling stocks) has fallen by over 9% since July 1, after a strong performance in the first half of the year. During the same period, the S&P 500 index rose by 2.8%, and the strategy is facing its largest quarterly underperformance in 25 years. Bank of America estimates that July was the second-worst month for momentum trading in nearly 40 years. Goldman Sachs data shows that the monthly underperformance of hedge funds' most-held stock basket relative to the S&P 500 in July was the largest in over 20 years. Biotechnology stock Moderna surged by approximately 150% due to positive news on its cancer vaccine, forcing many quantitative funds and hedge funds that were shorting the sector to cover their positions, becoming one of the triggers for this reversal.