Welcome to another issue of Net Interest, my newsletter on financial sector themes. Every Friday I distil 25 years experience of looking at financial institutions into an email that explores key themes trending in the industry. I’m grateful to all of you who have signed up, but don’t keep it to yourselves! Tell your co-workers, your cousins, your friends. Thank you.

The Cartographers of Finance

In nineteenth century England, cholera was a killer. For the first half of the century, no-one knew what caused it. The prevailing hypothesis was miasma—noxious bad air. John Snow, a prominent doctor working in London, had a different theory. He suspected the disease was spread via water. In 1854 an outbreak took hold in Soho and Snow went to investigate.

Snow pulled out a map of Soho and began to mark on it where the fatalities were. This map – reproduced below – would go on to become famous as one of the first examples of how geographic analysis can give us a better understanding of the world. I…