Supreme Court Curbs Tariff Powers, Shifts Focus to Treasury Supply

Janus Henderson’s Daniel Siluk assesses the Supreme Court’s decision to block the use of IEEPA for broad-based tariffs, reshaping trade leverage and bond market dynamics 

• The 6–3 ruling invalidates sweeping “reciprocal” tariffs, limiting executive authority and modestly reducing trade-policy tail risks for risk assets.

• Potential refunds of previously collected duties could create a sizable one-off fiscal cost, dependent on lower-court rulings.

• Any refund-related Treasury issuance may steepen the yield curve, pressuring long-end yields even as trade uncertainty eases.

Does reduced tariff volatility offset renewed fiscal supply risk? The full note examines cross-asset implications.