The head of the Bundesbank has sharply criticized the European Central Bank's plan to buy the debt of highly indebted states in a confidential report, according to German newspaper Handelsblatt.
In the 29-page report prepared for Germany's Constitutional Court, the Bundesbank warns that the purchase of such debt could "compromise the independence of the central bank" and could be difficult to stop, the paper said in an article made available on Thursday.
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The ECB launched the program - dubbed Outright Monetary Transactions (OMT) - last September to counter investor fears of a euro zone breakup. The plan immediately helped reduce the borrowing costs of heavily indebted states.
Bundesbank chief Jens Weidmann was the only ECB Council member to oppose the plan from the outset, which he described as "tantamount to financing governments by printing banknotes".
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The Constitutional Court, Germany's highest tribunal, is due to consider OMT in June, Handelsblatt said.
In its report for the court the Bundesbank noted that the OMT program could reduce the incentive for euro zone governments to reform.