What are AT1 bank bonds – and why are Credit Suisse’s wiped out?

Global banking system is under pressure amid row over who should lose out first when a bank struggles

• Nils Pratley: Swiss solve one problem at Credit Suisse, but create another for bondholders
• Comment: Bonds were seen as a safe haven – but they are central to this bank crisis

The global banking system is under renewed pressure after the Swiss government-brokered takeover of Credit Suisse by its larger rival UBS, after the deal wiped out the investment of bondholders who owned about $17bn (£14bn) of risky Credit Suisse debt.