In his book "The Ascent of Money," Niall Ferguson illustrates a critical lesson in finance: that size and diversification are crucial for risk management. By expanding their bank's scale and diversifying its activities, they mitigated potential threats that smaller institutions face. This approach allowed them to spread their risks effectively, ensuring greater financial stability.

Additionally, Ferguson highlights the importance of engaging in various financial activities, such as currency trading alongside lending. This diversification strategy not only protects against defaults but also positions the institution to better withstand market fluctuations, proving that larger and more varied banks can achieve resilience in challenging economic environments.