Last week, Fidelity Investments said it would close two institutional prime money-market funds with a total of around $14bn in net assets. That’s an ominous portent for some non-US banks, which have increasingly come to rely on such funds to raise dollars they can’t easily acquire at home.

Fidelity cited volatile outflows from the funds, which invest in short-term commercial paper and certificates of deposit issued by companies, and into government money-market funds during moments of market stress. Fidelity’s retail prime money-market funds, whose assets run into the hundreds of billions, will remain open.