Standard & Poor's today cut the credit rating of Deutsche Börse, the German stock exchange operator, after it announced a payout to shareholders of up to €448.4m ($586m).

S&P said the payout in the form of a share buyback "will weaken Deutsche Börse's capital" although its liquidity position will not be affected. The rating falls one notch to double-A. The agency also downgraded Clearstream, the exchange's settlement arm.