BRUSSELS (Reuters) - EU antitrust regulators have dropped charges against 13 banks including Citigroup (>> Citigroup Inc) and Deutsche Bank (>> Deutsche Bank AG) for blocking exchanges from derivatives markets, but will continue their case against data company Markit and trade body ISDA.

The European Commission said on Friday it had closed the case against the 13 banks due to insufficient evidence.

"This closure does not prejudge the outcome of the Commission's investigation regarding Markit, and ISDA, which is ongoing," it said in a statement.

Opened two years ago, the case was one of several launched by the EU's executive into financial services in the wake of the 2007-8 crisis. Regulators have handed down billions of euros in fines on lenders since then for misbehaving.

The Commission in July 2013 charged the group with blocking Deutsche Boerse (>> Deutsche Boerse AG) from the lucrative credit derivatives market in 2007 and the Chicago Mercantile Exchange in 2008.

"ISDA believes it has acted properly at all times. We will continue to cooperate with regulatory authorities to resolve this matter," a spokesman told Reuters.

The International Swaps and Derivatives Association (ISDA) represents firms involved in the derivatives market.

Markit was not immediately available to comment.

The 13 banks are Bank of America Merrill Lynch (>> Bank of America Corp), Barclays (>> Barclays PLC), Bear Stearns, BNP Paribas (>> BNP PARIBAS), Citigroup, Credit Suisse (>> Credit Suisse Group AG), Deutsche Bank, Goldman Sachs (>> Goldman Sachs Group Inc), HSBC (>> HSBC Holdings plc), JPMorgan (>> JPMorgan Chase & Co.), Morgan Stanley (>> Morgan Stanley), Royal Bank of Scotland (>> Royal Bank of Scotland Group plc) and UBS (>> UBS Group AG).

Three years ago, the Commission also scrapped a case against nine banks related to derivatives clearing because it did not have enough proof of wrongdoing.

(Reporting by Foo Yun Chee; Additional reporting by Huw Jones; Editing by Philip Blenkinsop and Mark Potter)

By Foo Yun Chee