What it is:
Market momentum is the perceived strength of a positive or negative change in market prices.
How it works (Example):
Market momentum is the ability of a market to sustain an increase or decrease in prices. Market momentum is a function of a price change during a specific period of time versus the trading volume during that period. In other words, high trading volume increases the market momentum of a price change and vice versa. For example, if the S&P 500 Index rises 100 between Monday and Tuesday in conjunction with heavy trading, the S&P is likely to sustain an upward trend in the days to come.