Congestion can test GENIUS stablecoin safeguards

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The Guiding and Establishing National Innovation for U.S. Stablecoins Act, or GENIUS Act, is the new federal framework for payment stablecoin issuers. Its reserve rules aim to make each token a safer dollar claim, while the public blockchains moving those tokens retain their own fee markets and capacity limits.

A Federal Reserve staff paper, first dated June 2, 2026, and updated Aug. 31, 2026, models how transaction congestion can destabilize even a perfectly backed digital dollar. The authors are Federal Reserve economists, and the paper carries the standard disclaimer that their views do not necessarily represent the Federal Reserve Board or Federal Reserve System.

When fees climb far enough, small payments become uneconomic and a token’s usefulness can fall. The model predicts that weak payment-network effects can then turn individual exits into coordinated redemptions. In the paper’s empirical work, however, “redemption” means a drop in Ethereum circulation and can include either a cash-out to fiat or migration to another blockchain.

The paper presents a latent mechanism, not a forecast of a current run. It sharpens an unresolved question as Treasury implements GENIUS: the law gives regulators broad tools for policing issuers, reserves and redemption promises, while its explicit reserve provisions and Treasury’s current section 3 proposal set no price or capacity standard for a public blockchain.

How congestion can trigger a run without bad reserves

Traditional stablecoin analysis starts with the issuer’s assets. If a token promises one dollar but its reserves lose value or cannot be sold quickly, holders have a reason to redeem before others do.

The Fed economists deliberately remove that problem from their model. The stablecoin is fully and safely backed. The source of fragility is instead the interaction between transaction fees and payment-network effects: people value a payment asset partly because other people accept and use it.

Under low congestion, that network can absorb a shock. Under high congestion and weak network effects, the paper finds a threshold beyond which redemptions can become coordinated and abrupt. Higher fees reduce use; reduced use makes the token less attractive; the weaker network then gives more holders a reason to leave.

“Redemption” needs care here. In the paper’s main empirical panel, it is measured as a negative change in a stablecoin’s Ethereum circulation. That can represent redemption for fiat, but it can also represent migration to another blockchain. The data therefore capture pressure on Ethereum-based circulation, not a clean count of customers cashing out at an issuer.

The study uses an unbalanced weekly panel of five stablecoins from November 2017 through December 2025 where data are available. Its starkest distributional result comes from 2021 through 2025: for below-median USDC transfers, the fee-to-value ratio at the 75th percentile frequently exceeded 100%. For above-median transfers, it was almost never more than 5%.

The statistic describes the distribution of attempted and completed transfer economics rather than a claim that users routinely paid more in fees than they sent. During expensive periods, a representative network fee could exceed the value of many small transfers. A holder can avoid completing such a transfer, wait, batch activity or move through a custodian. The pattern shows how congestion can ration access by transfer size even while the token remains redeemable.

What the evidence establishes

The paper combines a theoretical model with several empirical tests. Those pieces answer different questions and should not be collapsed into one causal claim.

Evidence Result What it supports Limit
Weekly stablecoin panel A one-standard-deviation, $10.83 increase in gas was associated with a roughly 0.9 percentage-point rise in weekly redemptions when network effects were low Fee sensitivity is strongest when a token’s payment network is weak Gas alone was insignificant, and the result applies to the low-network-effects state
Ethereum empty-slot design The raw empty-slot rate averaged 0.7%; a one-standard-deviation increase of 0.004 corresponded to about $0.77 more gas A plausibly exogenous congestion shock raises fees The design identifies the capacity-to-fee link, not the later redemption response
1,230 matched ETH-Tron USDT transfers From May 2020 through December 2025, the average matched transfer was about $176 million; $1 more in lagged, demeaned gas was associated with 3% to 4% more net matched value moving from Ethereum to Tron Higher Ethereum fees coincide with cross-chain reallocation The association cannot identify every owner or establish the motive behind every transfer

Gas by itself was statistically insignificant in the weekly panel. The reported 0.9-point effect appeared only when high fees interacted with weak network effects, a state covering roughly 7% to 7.5% of observations. The pattern is consistent with the model’s threshold logic, while remaining a historical association rather than a universal causal estimate.

The empty-slot exercise offers a stronger causal design for the first link in the chain. Empty Ethereum blocks are plausibly unrelated to stablecoin demand but reduce capacity and push up gas. The design helps establish that a capacity shock can raise fees. It does not directly establish that the same shock caused every later redemption.

The matched-transfer analysis is an association as well. It links transfers of identical USDT amounts on Ethereum and Tron within a 60-minute window, consistent with a chain switch. The method cannot observe the beneficial owner behind every pair, establish the motive for each move or exclude every alternative explanation.

Together, the findings support a conditional warning, not a forecast: congestion can create an exit incentive, and some historical activity moved toward a cheaper rail when Ethereum became more expensive.

GENIUS protects the token, not every rail

The GENIUS Act requires permitted payment stablecoin issuers to maintain reserves at least one-to-one in specified liquid assets. It also requires public redemption procedures, disclosure of issuer purchase and redemption fees, monthly reporting, examination and certification, and regulatory standards covering capital, liquidity, diversification, operations and information technology.

Those rules address important failure modes: weak assets, opaque redemption promises, undercapitalized issuers and poor operational controls. They also give regulators a clearer path to supervise the entity that creates the dollar token.

Treasury’s Aug. 17 implementation proposal, published in the Federal Register on Aug. 18, focuses on section 3’s restrictions on offering or selling payment stablecoins in the United States. Comments are due Oct. 19. Treasury says the expected effective date for the issuer licensing framework is Jan. 18, 2027, with the broader digital asset service provider restriction expected July 18, 2028.