The Money Equation

Finance is the business of other people's money, and almost everyone is its customer. A household that keeps a checking account, carries a credit card, pays a mortgage, insures a car and saves for retirement has made promises to, and accepted promises from, a dozen firms, most of which it never deals with directly. The United States has the largest and most varied financial system in the world: more than 4,200 insured banks, the deepest capital markets, the largest asset managers and insurers, the card networks that set the price of most retail payments, and a fintech industry that has tried for two decades to rebuild all of it in software. Some of these companies have created value for generations. Many more have destroyed it, and in finance destruction tends to arrive suddenly: a bank that took forty years to build failed in about 36 hours in March 2023, a market maker lost most of its capital in 45 minutes, and a crypto lender that had promised double-digit yields froze its customers' money overnight.

The difference is rarely cleverness. This book argues that a financial company creates durable value only when four things are true at once, and that the factors multiply rather than add: if any is zero, the result is zero. Customers and counterparties must trust it with their money, and that trust must be deserved. The risk it takes must be priced correctly, over a whole cycle rather than the good years in the data. It must be able to reach customers for less than they are worth. And its balance sheet must survive the bad year, with the capital, liquidity and stable funding to absorb losses and withdrawals without forced sales. Around those four factors sit two forces that no company controls, the interest-rate cycle and regulation, which behave like weather: they do not decide whether a firm deserves trust or prices risk well, but they decide how long it can survive if it does not. Most of the failures in this book come from treating one of the four factors as given rather than earned, and most of the successes from a firm that kept all four in view when its competitors stopped.

The twenty-five chapters develop that view. Part I explains why finance is a business of trust, how it became a business, how financial firms earn money from one customer's checking account, card and mortgage, and why risk so often looks safest just before it is not. Part II follows the markets one by one: banks, investment banks and capital markets, asset and wealth management, insurance, payments, lending and credit, and the exchanges and market makers behind every trade. Part III examines what it takes to build products that work, from core systems, ledgers and open banking to fintech and neobanks, data and models, business models, distribution, and credit and fraud as limits on growth. Part IV covers crises and runs, regulation and supervision, financial crime and compliance, crypto and digital money, and how the American system compares with others. Part V turns to people: culture, incentives and risk, and how to build a financial company. Part VI reads five cases for the decisions behind them. Each chapter opens with a case, explains the mechanics it illustrates, and closes by naming the factor of the equation on which its case turned.