The recent hack of a Chinese banking giant reignited Wall Street’s long-running fears of disruptions to the short-term cash markets underpinning the global financial system.

Traders swiftly contained the cyberattack on the Industrial and Commercial Bank of China. But some said the incident exposed cracks in the multitrillion-dollar market for repurchase agreements, known as repo, where banks and hedge funds borrow cash mainly using Treasurys as collateral.