Sullivan & Cromwell has acted as counsel for BNP Paribas as the bank agreed to pay a record $9bn (£5.1bn) settlement for breaching US trade sanctions.

The French bank yesterday (30 June) pleaded guilty to charges of conspiracy and making false statements relating to transactions on behalf of Sudan, Iran and Cuba, which amounted to billions of dollars over a ten year period between 2002 and 2012.

The settlement is the largest sanctions violation pay out in history. The biggest previous penalty paid by a bank for violating US sanctions was HSBC's $1.9bn (£1.1bn) settlement in 2012 relating to transactions with Burma, Cuba, Iran, Libya and Sudan.

For the ongoing investigation and settlement, BNP turned to Sullivan & Cromwell's Karen Patton Seymour, co-managing partner of the firm's litigation group.

Earlier this month, Bloomberg reported that fellow New York elite firm Wachtell Lipton Rosen & Katz had also been instructed by BNP, though the firm was not named in final settlement documents.

Lead prosecutors were US attorney for the Southern District of New York Preet Bharara, assistant attorney general Leslie Caldwell and Jaikumar Ramaswamy, the Department of Justice's (DoJ) asset forfeiture and money section chief.

Altogether, BNP had to settle with the DoJ, the New York Southern District Court, the New York County District Attorney's Office, the US Federal Reserve, the New York State Department of Financial Services, and the US Department of the Treasury's Office of Foreign Assets Control (OFAC).

Bharara was also instrumental in bringing action against JP Morgan which resulted in the bank paying $2bn earlier this year to settle charges it overlooked warning signs of Bernard Madoff's Ponzi scheme.

Sullivan & Cromwell is also acting as advisors for Barclays in relation to accusations the bank, amongst several others, including BNP, has been involved in rigging rates in the foreign exchange market.

BNP are taking advice from Allen & Overy (A&O) in relation to the forex probe.