FRANKFURT (Reuters) - The success of the European Central Bank's bond purchases in pushing down the euro, which makes euro zone exports more attractive, was limited and largely happened before buying even started, Germany's central bank said on Monday.


The ECB does not explicitly target a weaker euro but President Mario Draghi has repeatedly acknowledged the importance of the exchange rate for inflation.


A Bundesbank study published on Monday shows ECB bond purchases caused a devaluation of 6.5 percent in the euro against the dollar between October 2014 and the end of last year, with most of that devaluation happening before the program was even announced in late January 2015.


"The bond purchases of the Eurosystem had no significant additional effect on the exchange rate other than signaling effects and related expectations," the Bundesbank said.


The euro has fallen by 20 percent against the dollar since late 2014, partly due to a tightening in the Federal Reserve's own monetary policy.


Bundesbank's President Jens Weidmann is among the biggest critics of the ECB's quantitative-easing program, arguing it finances indebted governments and could result in inflating bubbles on financial markets and, eventually, high inflation.

(Reporting by Andreas Framke)