The National Security Agency, the US electronic intelligence service, is investigating the cyber attack last October on the Nasdaq OMX exchange.

Joel Brenner, who headed US counterintelligence in the Bush and Obama administrations and now works at the law firm Cooley Godward Kronis, told Bloomberg: "By bringing in the NSA, that means they think they're either dealing with a state-sponsored attack or it's an extraordinarily capable criminal organisation" [ http://buswk.co/dYScb4 ]