US regulators have authorised Belgium's Euroclear Bank to expand a link that allows US banks to move assets directly into Europe for use as collateral, amid rising demand for high-quality securities to back trades.

The post-trade service provider, which settles more than €675 trillion of securities transactions per year, won approval from the US Securities and Exchange Commission in December to allow US broker-dealers to transfer US equities directly into Europe for use as collateral in the region.