Porter's Five Forces model analyzes five competitive forces that shape an industry: 1) rivalry among existing competitors, 2) threat of new entrants, 3) bargaining power of suppliers, 4) bargaining power of buyers, and 5) threat of substitute products. The model helps businesses understand the profitability and attractiveness of an industry sector by identifying its weaknesses and strengths. Analyzing these competitive forces can help companies improve their profitability by adjusting their strategy accordingly.