Better-than-forecast US jobs, retail sales and industrial production data have lowered expectations of a further round of policy easing by the Federal Reserve and 10-year Treasury yields have risen around 20 basis points this week, although other releases have disappointed.
With no policy response expected to the euro zone debt crisis before September and no signs of the situation worsening, Bunds were adrift and largely being dragged along by their US counterparts.
"It seems a bit of an aggressive opening but Treasuries have been heavy all night," a trader said.
"There's been no more bad news out of Europe and that's not good for anyone that had long positions, so we're trading very technically in a thin market and it's hard to fight the sell-off at the moment."
September Bund futures were 41 ticks lower at 141.00, their lowest level in seven weeks, after breaking through key technical levels and sliding more than a full point the previous day.