Risky Bank Debt Is Rationally Exuberant

What’s the canary in the overpriced-asset coal mine? One obvious tweety bird is the riskiest type of bank debt, known as perpetual additional tier one bonds. These securities allow regulators to wipe out investors if a bank fails, but to compensate they offer the highest yields for lending to financial firms. This specialized asset class’s credit spreads are tightening despite a surge in issuance. But it’s not the red flag you might at first think.

AT1 outperformance

I have argued previously that worsening government finances are propelling allocation out of theoretically risk-free sovereigns into corporate and financial debt. Yields in certain markets, particularly in the UK or US, are high because nations are borrowing so much.

For bank debt, strong equity markets are probably the more powerful influence. The European bank stock index is up more than 240% since the demise of Credit Suisse Group AG in March 2023, when $17 billion of its AT1 bonds were zeroed. So it's not surprising that the euro bank AT1 index has delivered a total return of nearly 50% since then. It was a major stress test, but the asset class has weathered it.

There's a lot more of a capital buffer before we approach anything like the euro crisis of more than a decade ago, which spawned these instruments. Regulators have fought hard to persist with the AT1 regulated debt structure to absorb capital losses. It may not be perfect but it's here to stay as switching to any alternatives would be too disruptive for debatable benefits.