TOKYO, Aug 21 (Reuters) - Japanese government bond yields declined across the curve on Wednesday, along with U.S. Treasuries, after concerns about Italy's government and Britain's tumultuous exit from the European Union fuelled demand for safe-haven assets.
The benchmark 10-year JGB yield fell half a basis point to minus 0.245%.
In the super-long zone, the 20-year yield fell 1 basis point to 0.080%, while the 30-year and the 40-year yields slipped 1.5 basis points each to 0.180% and 0.205%, respectively.
Key 10-year JGB futures added 0.01 point to 154.93, with a trading volume of 16,922 lots.
Investors sought JGBs, along with other traditional safe-haven assets such as Treasuries, as political turmoil in Italy, Britain and Hong Kong heightened uncertainties about global economic growth.
Meanwhile, the U.S. Federal Reserve will release minutes from its July meeting later in the day, and its Chairman Jerome Powell is scheduled to speak at Jackson Hole Symposium on Friday. (Reporting by the Tokyo markets team; Editing by Sherry Jacob-Phillips)