TOKYO, June 28 (Reuters) - Japan's benchmark 10-year JGB futures fell for a second day on Wednesday and yields rose after a 20-year bond auction in the previous session witnessed weak demand, with sentiment further hurt by U.S. Treasury yields higher overnight.
Benchmark 10-year JGB futures fell 0.28 yen to 148.54, extending Tuesday's losses after posting seven straight sessions of gains till Monday.
"The outcome of the 20-year auction in the previous day was not so good, and that weighed on investor sentiment today. Overnight U.S. Treasury traded higher and that was also a negative factor for the yen rates," said Keisuke Tsuruta, fixed income strategist at Mitsubishi UFJ Morgan Stanley Securities.
The 20-year JGB yield rose 1.5 basis points (bps) to 0.970%. The 30-year JGB yield rose 2.5 bps to 1.210%.
The 40-year JGB yield rose 2.5 bp to 1.370%.
The 10-year JGB yield rose 2 basis points to 0.390%.
Investors are also awaiting comments from the Bank of Japan Governor Kazuo Ueda at the European Central Bank Forum in Sintra, Portugal.
Ueda will be in a panel with the Federal Reserve Chair Jerome Powell, Bank of England's Andrew Bailey and European Central Bank's Christine Lagarde.
Markets are trying to find a clue on when Ueda will phase out his predecessor's massive stimulus including the yield curve control, which puts limit on the trading band of the benchmark 10-year bonds. (Reporting by Junko Fujita; Editing by Nivedita Bhattacharjee)