Momentum investing and value investing are two contrasting approaches. While momentum investing focuses on stocks that are currently performing well in the market, value investing involves buying stocks that are undervalued in the market. Value investors look for stocks that they believe the market has undervalued, with the expectation that their true value will be recognized eventually. Momentum investors, on the other hand, focus on the current trend of stock performance, betting on the continuation of that trend in the short term.