Rivalry among competing sellers is the degree of competition between firms in the same industry. It can affect the profitability and market share of the firms, and influence their strategies and decisions. Rivalry tends to be stronger when the demand is slow, the products are similar, the switching costs are low, and the capacity is high. Rivalry can also lead to innovation, differentiation, and customer satisfaction.

Rivalry among competing sellers is generally weaker when buyer demand is growing rapidly. This is because a fast-growing market offers more opportunities for expansion and growth for all the firms, without having to compete aggressively for a limited number of customers. A fast-growing market also reduces the pressure to cut prices or increase advertising, as the demand exceeds the supply. A fast-growing market can also attract new entrants, which can increase the rivalry in the long run, but in the short run, it can create more diversity and segmentation in the market.

References: Competitive Rivalry: What Is It and Why Is It Important? | Indeed.com; Industry Rivalry & Competition | Porter’s Five Forces.