Why don't stablecoins pay interest while tokenized Treasury funds do?

Under US law a stablecoin is a payment instrument, not a deposit: the GENIUS Act explicitly bars issuers from paying holders interest "in any form". Income from reserves held in Treasury bills stays with the issuer. A tokenized Treasury fund is a share in a money market fund, which makes it a security: the yield goes to the holder, but so do identity checks, transfer restrictions and fund-level risks.

What exactly does the stablecoin law prohibit?#

Section 4(a)(11) of the GENIUS Act states that no permitted or foreign payment stablecoin issuer may pay a holder "any form of interest or yield" — in cash, tokens or other consideration — solely for holding, using or retaining the coin. The same law requires 1:1 reserves in cash, deposits, Treasuries with a remaining maturity of 93 days or less and reverse repos, and monthly publication of the reserve composition on the issuer's website.

The law was signed on July 18, 2025 and takes effect on January 18, 2027, when issuers will need a federal or state license, according to the US Treasury. On August 17, 2026 Treasury proposed rules defining when issuing and selling a stablecoin counts as happening "in the United States". According to a Reap overview, similar interest bans exist in the EU, UK, Hong Kong, Singapore, Japan and the UAE.

Where does the reserve income go instead?#

Large issuers' reserves are mostly short-dated US government debt. Briefs Finance reported on September 4, 2026 that Tether holds about $134 billion in Treasury instruments and repos and Circle about $63 billion. The issuer earns the coupon and discount; the coin holder gets the right to redeem at $1. That makes a stablecoin closer to digital cash: convenient for settlement and parking dollars between trades, but not growing on its own.

The trade-off is deliberate. Lawmakers separate the payment instrument from the investment product so that stablecoins do not compete with bank deposits and stay outside securities regulation.

Why did the stablecoin market shrink in mid-2026?#

DefiLlama data cited by Reap show total stablecoin market cap peaked at $322.4 billion on May 17, 2026 and fell to $308.0 billion by August 13 — 4.5% below the high, though still 14.3% above a year earlier. Supply fell by $8.04 billion in June and $4.07 billion in July. Briefs Finance estimates USDT lost about $3 billion in the first half of 2026 (to ~$184 billion) and USDC about $3 billion as well (to ~$72 billion).

There are several drivers. Analysts quoted by Briefs link part of the outflow to traders leaving exchanges: in a weak market fewer dollars sit idle waiting for trades. Reap points to a second one: investors who want a digital dollar with yield close to T-bill rates are moving into tokenized Treasury funds.

How does a tokenized Treasury fund differ from a stablecoin?#

As of September 23, 2026, RWA.xyz tracks $14.93 billion in tokenized Treasury funds (−4.78% over 30 days), 82,841 holders and an average 7-day yield of 3.50% APY. The largest products are Circle USYC ($2.51 billion), Ondo USDY ($2.27 billion) and BlackRock BUIDL ($2.23 billion). The whole segment is roughly 20 times smaller than the stablecoin market.

The mechanics differ. BUIDL, as described by Eco, keeps its token at about $1 per share and pays yield monthly as newly minted tokens. But only "qualified purchasers" under the US Investment Company Act may buy it, the minimum subscription is $5 million, and transfers are allowed only between KYC-checked, whitelisted wallets. You can send a stablecoin to any compatible address; a fund share you cannot.

Where does this approach fail, and what risks does the reader take?#

• Yield is not guaranteed. 3.50% is today's segment average; it tracks Fed rates and will fall with them. A money market fund share can, rarely, drop below $1.
• Access is limited. Most institutional tokenized funds are closed to retail investors, and redemptions go through the manager, on business days and not always instantly.
• Weak payment utility. Fund shares are poor collateral or settlement assets: few venues accept them, and whitelists block transfers to arbitrary addresses.
• Tax and jurisdiction. Fund income is usually taxed as investment income; rules vary by country.
• "Stablecoin yield" from an intermediary is a separate product. The statutory ban targets the issuer. If a platform promises interest on stablecoins, that income comes from its own activities — lending, staking, marketing budgets — and carries that platform's risk, not the issuer's reserve risk.

What does this mean for an ordinary stablecoin holder?#

It helps to separate jobs. For settlement, transfers and holding dollars between trades, a stablecoin fits: it earns nothing but is liquid and moves without recipient restrictions. For holding dollars longer with a return, regulated products exist — tokenized or conventional money market funds — but each comes with its own access rules, redemption timelines and taxes. Before choosing either, check who the issuer is, where the reserves sit, how redemption works and who actually pays the yield.