https://www.theguardian.com/business/2020/aug/22/five-factors-behind-the-us-stock-markets-miraculous-turnaround

Despite looking anything but fearless as Covid-19 first struck, US markets have regained lost ground and reached new highs. We list the reasons why

Nothing like the recovery in the US stock market has ever been seen before. After the Wall Street Crash of 1929, the time it took for shares to regain their previous peak was measured in decades. After the global financial crisis of 2008, it was measured in years. This time it has taken less than five months – from a low on 23 March – for the S&P 500 to regain all its lost ground and hit a new high. At the time, not even the most bullish trader would have been bet on such a rapid recovery, but five factors explain the remarkable turnaround.