Which stablecoin rules tightened this week?

TLDR

Several jurisdictions tightened stablecoin rules this week. The United Kingdom proposed temporary holding caps and stricter reserve rules for systemic GBP stablecoins, while Brazil finalized rules treating many stablecoin transfers as foreign exchange, and Singapore signaled tougher oversight ahead.

1. United Kingdom: temporary caps of 20,000 per person and 10 million per business for systemic GBP stablecoins, plus a 60% gilts and 40% central bank deposit reserve mix, per a new consultation by the Bank of England with temporary holding limits.
2. Brazil: stablecoin purchases, sales, and some wallet transfers classified as foreign exchange operations, with a $100,000 cap for transactions involving unauthorized counterparties and licensing for providers, under Resolutions 519521 %%CKPROTECTED0%%.
3. Singapore: MAS warned unregulated stablecoins are not suitable as settlement assets and said legislation under its stablecoin framework is being finalized, signaling a stricter regime outlined in remarks this week.

Deep Dive

1. UK caps and reserves

The Bank of England opened consultation on systemic sterling stablecoins used at scale in payments, proposing temporary holding caps and specific reserve composition.

1. Individuals would be capped at 20,000 per coin and most businesses at 10 million, framed as transitional safeguards to protect bank deposits during adoption, with exemptions possible and removal once risks subside per the consultation.
2. Issuers may hold up to 60% of reserves in short?term UK government debt and 40% as non?remunerated deposits at the BoE, with temporary flexibility during early growth as summarized here.
3. Non?systemic stablecoins used mainly for crypto trading (for example, USDT and USDC) remain under FCA oversight and are outside these specific caps per the same consultation.

2. Brazils FX classification

Brazils central bank finalized rules integrating stablecoin activity into its financial perimeter, emphasizing AML and formal FX treatment.

1. Purchases, sales, and exchanges of fiat?pegged stablecoins, plus certain domestic and cross?border transfers, are classified as foreign exchange operations under Resolutions 519521 %%CKPROTECTED0%%.
2. Transactions involving unlicensed foreign counterparties are capped at $100,000 per transfer, and VASPs must obtain authorization and meet banking?style compliance standards under the same framework.
3. Effective dates start in 2026, but firms will need to adapt licensing and processes ahead of time as reported.

3. Singapores tightening signal

Singapores MAS indicated upcoming tightening for unregulated stablecoins and stressed reserve quality and redemption certainty.

1. MAS said unregulated stablecoins have a patchy peg record and are unsuitable for large?value settlement, and it is finalizing legislation under its single?currency stablecoin framework outlined in remarks this week.
2. The direction prioritizes strong reserves, reliable redemption, and well?supervised issuers before stablecoins can be considered settlement?grade per the same speech.

Conclusion

This weeks moves point to a common pattern. Payment?grade stablecoins face caps and tighter prudential rules in the UK, Brazil is pulling stablecoin flows into formal FX channels, and Singapore is closing the door on unregulated models. The practical impact is greater reliance on licensed rails, stronger reserves, and clearer segregation between payment?system stablecoins and trading?focused tokens.