Citigroup pays $7bn in settlement

Another of America's biggest banks has had to bite the bullet over the country's sub-prime mortgages scandal, and pay $7bn dollars to the US Justice Department.

Citigroup has followed, reluctantly, in the footsteps of JP Morgan, which had to pay $13bn dollars. Bank of America is currently in negotiation with the Justice Department.

It was the sale of mortgage backed securities, often described as "shoddy" or "toxic", which led to the financial crisis of 2008, after which much of the global economy went into crisis.

We talk with Prof John Coffee, director of the Centre on Corporate Governance at Columbia University Law School.