TOKYO, May 7 (Reuters) - Japanese government bond (JGB) prices fell on Thursday after U.S. Treasury yield jumped following an increase in auction sizes, while investors became cautiously optimistic as several economies began to gradually reopen from coronavirus lockdowns.
Benchmark 10-year JGB futures fell 0.34 point to 152.27, with a trading volume of 10,093 lots.
U.S. Treasury on Wednesday sharply raised the size of its long-dated debt auctions and said it will launch a 20-year bond to finance expanding deficit caused by the COVID-19 pandemic.
The amount the Bank of Japan (BOJ) offered to buy for short to mid-dated JGBs was unchanged from its previous operation at the end of April, with 340 billion yen ($3.20 billion) for 1-3 year zone and 370 billion yen for 5-10 year zone.
The 10-year JGB yield rose 2.5 basis points to minus 0.005%.
At the shorter end of the market, the two-year JGB yield rose 1.5 basis points to minus 0.150%, while the five-year yield rose 2 basis points to minus 0.125%.
In the super-long zone, the 20-year JGB yield as well as the 30-year JGB yield rose 2 basis points each to 0.330% and 0.450%, respectively.
The 40-year JGB yield rose 1.5 basis points to 0.455%. ($1 = 106.2600 yen) (Reporting by Eimi Yamamitsu; editing by Uttaresh.V)