Following its failed attempt to take over the London Stock Exchange, German stock market operator Deutsche Börse is looking to strengthen its ties with the Swiss stock exchange SWX in Zurich, the head of the German company said in a newspaper interview Tuesday. "We're currently looking at ways of extending our already successful cooperation with SWX into other areas, such as the cash market," Mathias Hlubek, Deutsche Börse's interim chief, told the business daily Handelsblatt. "We're in close contact with our partner SWX," Hlubek added. The Frankfurt and Zurich exchanges already cooperate in futures trading -- they are joint owners of Eurex, the world's leading futures exchange. Hlubek insisted, however, that the two exchanges were not considering a straightforward merger. Deutsche Börse hoped to take over SWX last year, but the plans ran aground on resistance from Swiss banks. Hlubek, Deutsche Börse's chief financial officer, is currently acting as the German exchange's interim chairman following the stormy departure of chief executive officer Werner Seifert in May.