What it means
The story is that a reporter asked the bank robber Willie Sutton why he robbed banks, and he answered with the obvious reply. Sutton himself later said that he never said it, so the quote is probably a legend.
The saying survived because it captures a practical truth: the right target is the one with the biggest payoff. In finance, the rule is a prioritisation tool.
If a company wants to cut costs, it should start with the biggest expense categories rather than with the small ones that are easy to see. If an auditor wants to find errors, the sensible place to look first is the accounts with the largest balances and the highest risk.
The rule also warns against working on easy but unimportant problems. It can feel productive to trim the stationery budget or tidy a small account, but those actions barely move the total.
Management time is limited, so applying the rule helps point it towards the items that matter most. The rule is also handy in everyday meetings.
When a team is debating a long list of options, asking where the largest amount sits quickly cuts the discussion down to a few items worth the time. It keeps conversations about savings, risk and investment tied to real dollar amounts.
It is related to the Pareto principle, which says that a small number of causes often produce most of the effect. Both ideas encourage ranking items by size and starting from the top.
The difference is that the Willie Sutton Rule is simpler and more of a mental prompt than a formal analysis. The rule has limits, because the obvious target is sometimes the wrong one.
The largest cost may be fixed and impossible to cut, or small, frequent errors may add up to a bigger problem. Good analysts treat the rule as a starting point and then check whether the biggest item can actually be changed.
In practice
Real-world examples.
Example
A CFO asked to cut costs by $500,000 reviews the cost list and finds that two suppliers account for 45% of external spending. She starts negotiations with those two rather than reviewing dozens of small vendors.
Example
An internal auditor has two weeks to test a retail chain's accounts. She concentrates on cash handling in the highest-volume stores and on the largest supplier payments, since that is where a loss would be largest.
Example
A hospital administrator investigating rising costs finds that a few departments account for most of the overspend. Instead of a general cost freeze, he targets those departments for review.
Formula
Calculation
Share of total = Category amount / Total amount x 100
Suppose a company spends $5,000,000 a year, split into payroll of $3,000,000, cloud hosting of $1,200,000, travel of $500,000 and office supplies of $300,000. Payroll is 3,000,000 / 5,000,000 x 100 = 60% of the total, hosting is 24%, travel is 10% and supplies are 6%. A 10% saving on payroll is worth $300,000, while a 10% saving on supplies is worth only $30,000.Case study
Seen in the real world.
Greenfield Logistics is a fictional transport firm, and this is an illustrative case. The new CFO wanted to cut $1,000,000 from a cost base of $20,000,000 and received a list of 60 ideas from staff. Most were small, such as cutting printing and changing coffee suppliers.
Applying the Willie Sutton Rule, she ranked the costs and found that fuel and vehicle maintenance together made up 55% of the total, or $11,000,000. A fuel purchasing agreement and a maintenance schedule review brought savings of $900,000 within a year, while the small ideas together would have saved less than $80,000. The illustrative lesson is that the biggest line is where effort pays off the most.
Watch out
Common mistakes.
- Focusing on small, easy savings because they are visible, when they barely change the total.
- Assuming the biggest cost is always the best target, when it may be fixed or already efficient.
- Using the rule to ignore small risks, when frequent small errors or a hidden fraud can matter more than their size suggests.
Questions
People also ask.
Did Willie Sutton really say it?
He denied it, saying a journalist made up the line, so the quote is best treated as a popular legend.
How is it different from the Pareto principle?
The Pareto principle describes how a few causes produce most effects, while the Willie Sutton Rule is a simple instruction to start where the largest amounts are.
Where else is the rule used?
It is used in medicine, auditing, fraud investigation and project management, wherever limited effort must be pointed at the likeliest or largest problem.
From the founder's library
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