Banks will struggle to raise much capital through issuance of so-called contingent convertibles (CoCos) - bonds that convert into equity when a bank is under pressure - according to panellists at Risk Europe's Basel III summit in Brussels this afternoon, with one comparing them to "snake oil". One CoCo issuer even voiced fears the debt could actually increase pressure on a bank.

But the main objection was that traditional investors would see the bonds as too risky. "Widows and orphans should not