Three months ago, the oldest bank in the world took a very 21st-century financial instrument and produced something new in global finance. Italy’s Banca Monte dei Paschi di Siena, founded in 1472, arranged for interest rate swaps – a type of derivative used to insure against rate fluctuations – to be processed through a London clearing house.

The move sounds arcane. But pushing derivatives into clearing houses is an important part of reforms initiated by the Group of 20 leading nations and now being implemented to help safeguard the system against another Lehman Brothers-style default.