谁在4月抄底美股？散户和公募基金，对冲基金和CTA仍然谨慎

Group 1 - The core viewpoint of the articles is that the U.S. stock market experienced a significant rebound in April, with the S&P 500 index recovering 50% of its year-to-date losses [1] - Retail investors and mutual funds were the main drivers behind this rebound, while hedge funds and CTA funds remained cautious with low risk exposure [2][7] - Retail investors recorded a net buying amount of $40 billion in April, marking the largest single-month inflow on record [3] Group 2 - Mutual funds took advantage of the market pullback, increasing their positions significantly, influenced by the "Trump put" effect, which suggests potential government measures to alleviate market pressure during downturns [4] - Hedge funds and CTAs maintained a conservative stance, with low risk exposure levels, indicating a need for further decline in volatility before they significantly increase stock holdings [7] - UBS strategists are optimistic about a potential return of CTA funds to the stock market in May, estimating a possible buying scale of $20-25 billion in the next two weeks [10] Group 3 - Despite positive signs such as market breadth recovering from extreme oversold levels, the VIX and VSTOXX indices remain above 20, indicating ongoing market pressure [11] - Options have become a tool for some investors to bet on the continuation of the rebound, with recommendations to buy short-term, low-cost call options on the Nasdaq 100 ETF [13] - The macroeconomic uncertainty, particularly regarding tariff negotiations, continues to cast a shadow over the market, although there may still be room for further recovery if macro momentum does not significantly deteriorate [13]