EU antitrust regulators accused MasterCard on Thursday of over-charging non-European cardholders to process their purchases in Europe, the second time the EU has taken on the world’s No. 2 credit and debit card network. The latest move by the European Commission came after a two-year long investigation and is part of its efforts to trim such fees and boost cross-border trade. MasterCard capped its cross-border interchange fees, which are levied on retailers’ credit and debit card transactions, in 2009, after the EU competition enforcer said the high level of charges breached antitrust rules.