The payment processing industry has high barriers to entry due to economies of scale, large fixed infrastructure investments, and strong network effects. The three large incumbent players, Visa, Mastercard, and American Express, cooperate to reinforce each other's competitive advantages and collectively control over 90% of the market. They also exert market power over merchants through no-discount policies and colluding to raise interchange fees. As a result, the industry enjoys very high profitability as evidenced by returns on capital of 60-70%, operating margins of 50-60%, and stock returns over 100% in the last 5 years.