Stablecoin issuers are quietly becoming America's marginal Treasury buyer
China's Treasury holdings fell to $590.7B in August 2026, an 18-year low. Stablecoin issuers added about $200B in five years. The scale check matters as much as the headline.
For two decades, the question hanging over the market for United States government debt was who would replace the foreign central banks. Foreign investors held more than half of outstanding Treasuries around 2008; by early 2026 their share was down to about 30% (Federal Reserve Bank of San Francisco, September 28, 2026). China's reported holdings tell the retreat in one line: a peak of about $1.32 trillion in November 2013, down to $590.7 billion at the end of August 2026 — the lowest level since August 2008 (U.S. Treasury, Treasury International Capital data released October 16, 2026). Part of the gap is now being filled by a buyer that did not exist as a market force a decade ago and does not fly a flag: stablecoin issuers, the companies behind dollar tokens such as Tether's USDT and Circle's USDC.
The August numbers: a changing of the guard, in slow motion
The latest Treasury International Capital (TIC) release — the Treasury Department's monthly census of who holds U.S. securities — put total foreign holdings at $9.332 trillion at the end of August 2026, up from $9.248 trillion in July 2026 (U.S. Treasury, released October 16, 2026). Demand did not disappear. It changed hands.
- Japan stayed the largest foreign holder at $1.0683 trillion, down $35.6 billion in the month (U.S. Treasury TIC, August 2026).
- The United Kingdom rose to $1.0095 trillion, crossing $1 trillion for the first time — though London is a global custody centre, so securities booked there can belong to investors from anywhere (U.S. Treasury TIC, August 2026).
- China fell for a third straight month to $590.7 billion, down about 16% from a year earlier (U.S. Treasury TIC, August 2026).
Read those three lines together and the story is rotation, not collapse: official Asian holders are trimming, custody centres and private buyers are absorbing, and the total is still rising. Stablecoin issuers sit inside that rotation — small in the total, but growing faster than any of the names on the TIC table.
How big is the stablecoin bid, exactly?
The cleanest measurement comes from the Federal Reserve Bank of San Francisco's Economic Letter of September 28, 2026. Looking at the two largest issuers — Tether and Circle, which together account for more than 80% of stablecoin market value as of mid-August 2026 — the researchers found that their holdings of U.S. Treasury securities and Treasury-backed repurchase agreements grew more than tenfold in five years, an increase of approximately $200 billion. That increase offsets more than 40% of the reduction in China's holdings over the same period. Since 2023, the letter adds, stablecoin issuers have accumulated short-term Treasuries faster than Japan, the largest foreign holder overall.
A repurchase agreement, or repo, is a short-term loan collateralised by securities — here, an issuer lending cash overnight against Treasury collateral. It finances Treasury holdings rather than owning the bond outright, which is why careful readers separate the two. The SF Fed figure combines bills owned and repo; it is a footprint measure, not a pure ownership count.
The issuer-level disclosures line up with the aggregate:
- Tether held $114.96 billion directly in Treasury bills at June 30, 2026, plus $25.6 billion in overnight and term reverse repurchase agreements, against total assets of $187.75 billion and liabilities of $183.64 billion (Tether attestation by BDO, Q2 2026). Counting direct and indirect exposure, Tether puts its Treasury footprint at roughly $140.6 billion — a scale its coverage compares to a mid-sized sovereign holder.
- Circle holds USDC reserves mainly through the Circle Reserve Fund, a government money market fund managed by BlackRock that holds short-dated Treasuries and overnight Treasury repo, with the remainder as cash at large banks; USDC in circulation was $73.3 billion at the end of Q2 2026 (Circle, Q2 2026 results). A Council of Economic Advisers analysis in April 2026, citing Circle's December 2025 reserve report, put about 88% of USDC reserves in bills and repo and about 12% in bank deposits.
- The official sector sees the same total from the other side: a Deputy Treasury Secretary said on September 22, 2026 that stablecoin issuers already hold nearly $200 billion in Treasury bills and other short-dated Treasury securities (U.S. Treasury remarks, September 22, 2026).
The new buyer is not a government deciding to fund America. It is a reserve rule deciding for thousands of token holders at once — every new dollar of stablecoins in circulation becomes, mechanically, most of a dollar of demand for short-term U.S. debt.
Why the buying is structural, not discretionary
A finance ministry buys Treasuries as a policy choice and can change its mind. A stablecoin issuer buys them as a business and legal requirement. A stablecoin promises redemption at one dollar on demand; the assets behind that promise have to be liquid enough to meet redemptions on the worst day, not the average one. Short-term Treasury bills — government debt maturing in weeks or months — are the deepest, most saleable dollar asset there is. That is why issuers concentrated there even before any law told them to.
The law now tells them to. The GENIUS Act, enacted July 18, 2025, requires permitted U.S. payment stablecoin issuers to back tokens at least one-for-one with a short list of permitted reserves: cash, deposits at insured banks, Treasury bills with 93 days or less to maturity, overnight repurchase agreements backed by Treasuries, government money market funds, and central bank reserves. Issuers may not pay interest or yield to holders. The Act's main obligations take effect on January 18, 2027 at the earliest. In other words, Congress has written the reserve portfolio into statute: as regulated stablecoins grow, bill demand grows with them, automatically.
That mechanical link is also why the price effect, while small, is measurable. A Bank for International Settlements working paper (BIS Working Paper 1270) estimates that a $3.5 billion stablecoin inflow lowers three-month Treasury bill yields by about 2 to 2.5 basis points within ten days in its most stringent specification — a basis point is one hundredth of a percentage point — with no material effect found further out the yield curve. Small numbers, but they are the signature of a marginal buyer: not big enough to set the price of U.S. debt, big enough to move the price at the short end where it actually trades.
The honest scale check
This is where the story is usually oversold, so here are the denominators. Total U.S. Treasury securities outstanding were $31.8 trillion as of September 2026 (SIFMA, September 2026), and total public debt outstanding was $40.17 trillion at September 30, 2026 (U.S. Treasury FiscalData). Against those figures, roughly $200 billion of issuer holdings is well under 1% of the market. Money market funds hold trillions, not billions. If every stablecoin vanished tomorrow, the Treasury would still fund itself.
Three qualifications keep the marginal-buyer claim honest rather than hype:
- It is a flow story, not a stock story. Issuers matter because of the speed and direction of their buying — more than tenfold growth in five years, faster short-term accumulation than Japan since 2023 — not because of their share of the total.
- The maturities do not match. China's decline is concentrated in longer-dated securities, while issuers buy bills of 93 days or less under the GENIUS Act menu (Federal Reserve Bank of San Francisco, September 28, 2026). Issuer demand supports the front end of the curve; it does not replace the long-term funding China used to provide.
- The projection is a projection. If recent growth trends continue, the SF Fed researchers estimate issuer demand could reach around $400 billion by the end of 2030. That is a trend extrapolation, not a forecast with a guarantee — it depends on stablecoin adoption, on who buys the tokens, and on regulation holding its current shape.
Foreign official demand for Treasuries is retreating — China's holdings are at an 18-year low — and regulation has created a replacement buyer at the margin: stablecoin issuers, whose reserves must sit in T-bills and overnight repo. At roughly $200 billion they are still under 1% of the market, but no other buyer is growing as fast, and their demand is written into law rather than left to discretion.
The risks and open questions
01A buyer that can be forced to sell
The same redemption promise that makes issuers buy bills makes them potential forced sellers. If token holders redeem heavily in a panic, an issuer must raise cash quickly, and the fastest cash is selling bills or letting overnight repo run off. Federal Reserve researchers have flagged exactly this channel: stress at a large issuer could transmit into the bill market itself, because that is where the reserves are. A marginal buyer in calm times can be a marginal seller in bad ones.
02Concentration in two balance sheets
More than 80% of the stablecoin market sits with two issuers (Federal Reserve Bank of San Francisco, September 28, 2026). The "new class of Treasury buyer" is, in practice, Tether and Circle and their reserve managers. That concentration is a transparency question as much as a market one: the market's visibility into this demand comes from one issuer's quarterly attestations and the other's monthly ones, not from the TIC census, which does not break issuers out as a category.
03Bills are not bonds
Issuer demand lands almost entirely at maturities under a year, and under 93 days for GENIUS Act reserves. The Treasury still has to sell long-term debt to someone. If bill demand from issuers lets the Treasury issue more short-term debt instead, the funding mix shortens — cheaper when bill yields are compressed, but refinanced far more often. Whether that trade is wise is a debt-management decision, not a stablecoin decision.
For the background on how these tokens work, see stablecoins, explained; for how the card networks are building on top of them, see Visa vs Mastercard: both card networks just put stablecoins into production; and for how agents spend them, see agent payments, explained.
Key terms
- Treasury bill (T-bill)
- U.S. government debt maturing in one year or less, sold at a discount and repaid at face value.
- TIC data
- Treasury International Capital: the Treasury Department's monthly census of foreign holdings of U.S. securities, by holder country.
- Marginal buyer
- The buyer whose additional demand is large or fast-growing enough to affect prices at the edge of a market, even if its total share is small.
- Repurchase agreement (repo)
- A short-term loan collateralised by securities; overnight repo backed by Treasuries is a permitted stablecoin reserve under the GENIUS Act.
- GENIUS Act
- The 2025 U.S. law creating a federal framework for payment stablecoins, including one-for-one reserve backing in cash, short-term Treasuries and similar liquid assets.
- Attestation
- An independent accountant's report confirming an issuer's reserve assets at a point in time; narrower than a full audit.
- Basis point
- One hundredth of a percentage point (0.01%); the unit in which small yield moves are quoted.