What is float, and who earns it?
Between the moment you pay and the moment it arrives, the money is sitting somewhere, and somebody is earning on it.
The money exists on Tuesday. It is simply not with either of the two people who think they own it.
The gap is the product
Every payment has a gap. You are debited on Monday. The merchant is credited on Wednesday. On Tuesday, that money exists, and it is somewhere.
Multiply one balance across millions of transactions and the pattern becomes an asset. A company holding an average of a few hundred crore of other people's money overnight, every night, is earning meaningful interest on money it does not own.
This is not a loophole. It is one of the oldest revenue lines in finance, and for long stretches it was the quiet reason certain businesses worked at all.
Four places it is hiding right now
Wallets and prepaid balances. Money you loaded and have not spent is float. Regulation requires it to sit in an escrow account with a bank, which protects you, and interest on that escrow is a live regulatory question in several markets.
Settlement delays. The gap between a card sale and the merchant's deposit.
Cross-border pre-funding. Money parked in a foreign account before anyone asks to send it there.
Unspent gift cards and stored credit, which is float that sometimes never gets claimed at all.
Why it is shrinking, and what replaced it
Instant rails compress the gap. When settlement moves from days to seconds, the float evaporates. This is a genuinely underrated force in payments: a large slice of the industry's historical economics is being deleted by speed.
Which is why business models moved. As float disappeared, companies shifted to fees, lending, subscriptions and data. The pattern of the last decade is not that payments got cheaper by accident. It is that one revenue line quietly died and the industry had to find another.
A cloakroom that holds a thousand coats. It does not own a single one, and every coat will be collected. But there is never a moment when the room is empty, and a room that is never empty can be used for something.
Where you meet it
Every balance sitting in an app you forgot about, every refund that takes five days, and every service that is suspiciously happy for you to top up in advance.