Float

Float is other people's money that sits in your account before you have to pass it on — and the returns you earn on it in the meantime. The concept is simple. The consequences are extraordinary. Warren Buffett built the greatest compounding machine in financial history on float, and most people who study Berkshire Hathaway still underestimate how central it was.

The insurance industry invented the dynamic. When you pay your car insurance premium in January, the insurer doesn't need that money until a claim arrives — maybe in March, maybe never. In the gap between collecting premiums and paying claims, the insurer holds the cash. That cash is the float. It doesn't belong to the insurer. It will eventually be paid out. But while it sits there, the insurer can invest it — in bonds, stocks, real estate, entire companies. The investment returns belong to the insurer, not the policyholder.

Buffett recognised this in the 1960s and spent the next six decades engineering the largest float pool in corporate history. Berkshire's insurance subsidiaries — GEICO, General Re, Berkshire Hathaway Reinsurance — collected premiums from millions of policyholders. By 2023, Berkshire's float exceeded $167 billion. That is $167 billion of other people's money that Buffett invested at his historical return on equity — north of 20% for decades. The float cost Berkshire nothing in most years because its insurance operations broke even or turned an underwriting profit. In years when underwriting was profitable, the float had a negative cost: Berkshire was being paid to hold other people's money. The economic equivalent is a bank that charges negative interest on deposits — the depositor pays the bank to keep their cash, and the bank invests it. No rational person would accept that deal, yet insurance policyholders accept it every day because they're buying risk transfer, not making an investment decision.

The insight extends far beyond insurance. Amazon holds seller funds for approximately two weeks before disbursing — during which time Amazon invests or deploys that cash. With over two million active sellers generating hundreds of billions in gross merchandise value, the float is enormous. PayPal held $36 billion in customer balances as of 2023 — funds sitting in PayPal accounts between receipt and withdrawal. Credit card companies operate on float by design: Visa and Mastercard process transactions where merchants wait 1–3 business days for settlement while the card network holds the funds. Travel agencies, subscription platforms, prepaid card issuers, loyalty programmes — float exists anywhere money changes hands with a time delay between collection and disbursement.

The power of float is not the money itself. It is what happens when float meets compounding. A one-time $167 billion investment is valuable. A $167 billion pool that renews automatically — because new premiums flow in as old claims flow out — compounds year after year without requiring the capital to be raised, borrowed, or earned through operations. Float is self-replenishing capital. That is what makes it structurally different from debt, equity, or retained earnings, and that is why Buffett called it "better than free money."