As of the close today, just 16% of the stocks in the S&P 500 are trading above their 50-day moving averages. Below is a chart of this measure over the last year. As shown, only the crash last August saw a similarly violent move down to these deeply oversold levels.
Of the ten S&P 500 sectors, four now have readings below the 10% level — Energy, Industrials, Technology and Telecom. Health Care and Materials are both right at 11%. The two sectors holding up the best are Utilities and Consumer Staples. Unsurprisingly, these are the two most defensive sectors of the market.