Germany's bund yields boomed at the fastest pace in a generation this week

German bund (bond) yields have been on a tear this week. After speculation about when the yield on Germany's 10-year bunds would push below zero, they've come roaring back in the other direction. 

The yield dropped to just 0.059% on April 17 - it's now come screaming back to just shy of 0.70%. That may not sound like a major move, but it is in fact the biggest upward climb in a quarter of a century. 

Here's how it looks, from Reuters' Eric Burroughs: 

By historical standard yields are still incredibly low, but the recent upswing is clear visible even with a long-term view:

Investing.com, Business Insider

When the yield on a bond rises, it means the value of the asset itself is declining. That could be because investors expect stronger inflation in Europe, given the unexpectedly solid recovery that the eurozone has seen recently - that could mean a tapering of the European Central Bank's QE programme earlier than expected.