Libor: The Rise and Fall of ‘The World’s Most Important Number’

For half a century, the London interbank offered rate -- better known as Libor -- has been a constant presence in financial markets. After starting as a simple interest rate used in syndicated loans, its importance ballooned when banks began using it to determine the floating leg in derivatives contracts.

Before long it was a feature in everything from sub-prime mortgages and student loans to the $1 trillion in bailouts given to US banks during the financial crisis.