The rise in Germany's borrowing costs to a 15-year high reflects the increased security challenges facing the country following Russia's invasion of Ukraine and the need to spend much more defence, the Finance Ministry said on Wednesday. German 10- and 30-year borrowing costs hit a fresh 15-year high in Wednesday's session. Bond yields of other major Western economies including the U.S. and Japan have also climbed to multi-decade highs this week due to ballooning government debt and geopolitics, increasing borrowing costs for companies and households and complicating policy.