The newswire says the US Government agency sent civil investigative notices this month to banks that have shareholdings in Markit to determine if they have unfair access to price information.

“Markit has been informed of an investigation by the Department of Justice into the credit-derivatives and related markets,” spokeswoman Teresa Chick told Bloomberg News. She declined to comment on the nature of the investigation.

Citing "people familiar with the matter", Bloomberg says the notices ask recipients to give the Justice Department details on the amount of their trading, how much they have at risk in the market, the monthly value of their credit swaps and other information.

The letter also seeks the level of current bank ownership in Markit and whether the shareholders have tried to sell their stakes.