BIS Paper Flags Tradeoffs in Tighter Stablecoin Reserve Rules

A new working paper from the Bank for International Settlements is challenging a simple assumption that tougher stablecoin reserve rules automatically make issuers safer. Ledger Insights reported that the paper offers a formal analytical framework for comparing liquidity and capital thresholds as regulators in the European Union, the United States and other jurisdictions move toward more detailed supervision of fiat-backed stablecoins. The headline conclusion is not that rules are unnecessary, but that the design of those rules matters because different requirements change issuer behavior in very different ways.

The article places that debate in the context of two major regulatory approaches now coming into view. Under Europe’s MiCAR regime, at least 30% of stablecoin reserves must be held as bank deposits and issuers face explicit capital requirements. In the United States, the Office of the Comptroller of the Currency’s proposed rules for implementing the GENIUS Act would add a 10% true liquid floor and a 30% five-business-day accessibility requirement. Ledger Insights said the BIS paper is the first rigorous attempt to model how these thresholds interact rather than treating reserve composition and capital buffers as isolated policy levers.

In the model described by Ledger Insights, a fiat-backed stablecoin issuer has to decide both how much capital to raise and how to allocate reserves between cash and bonds. Cash is safer in a redemption event but does not earn income, while bonds offer yield but can become costly to sell quickly. The paper also assumes that redemption shocks have momentum, meaning a bad week for outflows is more likely to be followed by another bad week. That feature is based on weekly flow data from five major dollar stablecoins between 2020 and 2025, which the authors use to make the model behave more like the real market.

One of the paper’s central findings is that liquidity rules and capital rules do not produce the same response. Ledger Insights said a liquidity threshold pushes issuers to hold more cash, but does not materially change how much capital they raise. A capital requirement, by contrast, encourages issuers to raise more capital and also to hold more cash because the additional buffer reduces the chance that bonds would need to be sold at distressed prices, eroding equity in the process. In other words, capital requirements can influence both sides of the balance-sheet problem, while liquidity rules mainly affect one.

That asymmetry is important because stablecoin regulation is increasingly being built around reserve quality and redemption readiness. Policymakers often focus on how much of a reserve pool can be liquidated immediately, but the BIS framework suggests that capital design can shape issuer incentives in a broader way. If a rule set leans too heavily on rigid liquidity thresholds without accounting for capital structure, the result may not be the safest possible system. The paper therefore adds analytical support to a more calibrated approach in which reserve rules are tested for how they interact under stress rather than judged only by how conservative they look on paper.

For the RWA and stablecoin market, the significance is practical. Reserve assets, tokenized cash products and short-duration government instruments are increasingly central to the business model of regulated dollar tokens. As lawmakers finalize implementation details, the question is no longer whether reserves matter, but which mix of liquidity constraints and capital buffers produces the most resilient outcome. The BIS paper, as summarized by Ledger Insights, suggests that blunt reserve rigidity can create its own risks and that the next phase of stablecoin oversight will depend on finer-grained calibration rather than headline conservatism alone.