Stablecoin float

Stablecoin float is the money behind the money. Every token in circulation is backed by a dollar the holder handed to the issuer, and that dollar does not sit idle: it is invested in reserve assets, overwhelmingly short-term Treasury bills and cash placed with banks. The reserves make the token redeemable at par. The interest they earn, which the token holder does not receive, is the float, and it is the economic engine of the entire issuer business.

The scale is public in at least one case. Circle, the issuer of USDC, reported $2.7 billion of total revenue and reserve income for fiscal year 2025, up 64% year over year, and reserve income was 96% of the total. The shape of that disclosure is the point: issuing a stablecoin is, financially, the business of managing an interest-earning reserve pool whose size equals the tokens outstanding. Growth in circulation grows the pool; interest rates set the yield on it. Both levers sit outside the holder’s view, which is why float is the number to understand when reading any issuer’s incentives, including the incentive to keep tokens in circulation rather than redeemed.

The yield line the law drew

The obvious question the model raises is why the holder, whose dollar funds the reserve, earns nothing on it. For US payment stablecoins the answer is now statutory: the GENIUS Act prohibits issuers from paying interest or yield to holders on the stablecoin itself. The prohibition, whose scope regulators have proposed extending to affiliates and third parties acting in concert with issuers, does two things at once. It preserves the float model, and it marks payment stablecoins as payment instruments rather than investment products, keeping them outside the perimeter that yield would drag them into.

Where does the yield-seeking demand go? Around the prohibition rather than away: into tokenized money market funds, which are investment products and may pay yield, and into the live policy debate over whether banks’ tokenized deposits should carry interest as ordinary deposits do. That boundary, payment instrument on one side, yield-bearing claim on the other, is becoming one of the organizing lines of digital money regulation.

For the institutions that hold and move stablecoins at scale, float is also a quiet cost of carry. A balance parked in tokens is a balance earning the issuer’s yield rather than the holder’s, which is one reason treasurers think in terms of minimizing idle token balances, and why the economics of holding a stablecoin differ from holding the deposit that backs it.