Paying cash feels free, because no lender ever sends you a bill. Nelson Nash, who wrote Becoming Your Own Banker, built infinite banking on the opposite idea. Infinite banking means using a dividend-paying whole life policy as your own source of financing. Nash's point was that you finance everything you buy. Either you pay interest to a lender, or you give up the interest your own money would have earned. That chapter, and the three after it, are what Carlo Viqueira and I summarized in our LIFE Pod episode on the core problem in Nash's book.
Take a $30,000 car. Finance it at 7% for five years, and the payment is about $594 a month. Over the five years you pay about $5,640 in interest, and you know it because it's printed on the loan statement.
Pay cash from a savings account earning 4%, and there's no statement. The $30,000 stops earning, though, and that's about $1,200 of interest in the first year alone. You actually paid for the money either way. The cash buyer's cost just shows up as interest that never got credited.
In this example, paying cash still comes out ahead. If the cash buyer puts the same $594 a month back into savings for five years, he ends up about $2,750 ahead of the borrower, because the loan charged 7% and the savings only earned 4%. Nash wasn't arguing for the car loan. He was arguing that most households send so much of their income out the door as interest, on mortgages, cars, and credit cards, that it swamps what they manage to save. His fix was a pool of money that keeps earning while you use it.
For Nash, the pool was the cash value of a whole life policy. The policy credits a guaranteed rate, and a mutual company, which is one owned by its policyholders, adds dividends that aren't guaranteed. When you need money, you borrow against the cash value instead of withdrawing it, and the cash value keeps being credited while the loan is out, though some policies credit the borrowed portion at a different rate. I think of it as locking in compound growth. Once a policy starts compounding, it doesn't stop because you borrowed against it, which is the same idea behind one dollar doing two jobs.
Nash's rule for the car was to pay the policy back on the same schedule a lender would have set, including the interest the lender would have charged. Whatever you pay above the policy's own loan interest goes back in as extra premium, which builds the pool for the next purchase. His phrase for this was being an honest banker. A policy loan still costs interest, and it reduces the cash value and death benefit until it's repaid, so the payback habit is what makes it work. Policy loans vs. bank loans compares the two side by side.
Building the pool also takes time, and Nash called those early years the capitalization period. Designs today can make 80% to 90% of the first year's premium available as cash value, which is probably more than the policies Nash was designing back then. A new policy still can't buy a car on day one unless it was funded for it.
Next time you're about to pay cash for something over $5,000, look up what that money earns where it sits today. On $10,000 earning 4%, that's $400 a year you stop collecting until you've saved it back up.