European banks' use of synthetic risk transfers surged 27% last year, with Barclays analysts estimating €500bn in loans now protected through these structures — roughly 2-3% of the region's total lending. An SRT lets a bank offload loan risk to investors such as insurers and hedge funds, who post collateral covering first losses. In return, the bank frees up regulatory capital and can lend more, though the loans stay on its balance sheet.

The European sector has embraced SRTs more aggressively than U.S. peers, driven by a moribund traditional securitization market and pressure from the Basel 3 Endgame capital rules. AFME reported a 36% year-on-year jump in SRT volumes during the first quarter alone. Investors typically deposit collateral for the deal's duration, satisfying regulators that risk transfer is genuine.

Yet supervisors remain uneasy. Pedro Machado of the ECB's Supervisory Board warned that some structures may not truly move risk outside the banking system, that investors could recycle exposure back into banks, and that weakened monitoring incentives or adverse selection could bite. The IMF and Financial Stability Board have also flagged systemic concerns.

Regulators nonetheless back SRTs as a de-risking tool, and the market shows no sign of slowing. The real test will come when a large reference pool deteriorates — revealing whether collateral buffers hold and whether risk has genuinely left the system or merely migrated into shadow corners of it.