Before we spend days researching a stock idea we'd like to take a look at how hedge funds and billionaire investors recently traded that stock. S&P 500 Index ETF (SPY) lost 13.5% in the fourth quarter. Seven out of 11 industry groups in the S&P 500 Index were down more than 20% from their 52-week highs at the trough of the stock market crash. The average return of a randomly picked stock in the index was even worse.