The High-Low Index is a breadth indicator based on new highs and new lows made on Nyse. New high refers to the number of stocks reaching a new 52-week high. New low refers to the number of stocks reaching a new 52-week low. The index is calculated by dividing the number of new highs and the new lows by the number of total issues (new highs, new lows and unchanged issues). Both ratios are additionally smoothed by an exponentially moving average. The High-Low Index is a measure of underlying strength or weakness of the S&P 500.
Bullish: New highs above new lows
Bearish: New highs below new lows
Watch out for divergences between the market and advancing issues