SINGAPORE, April 12 (Reuters) - Super-long Japanese government bonds edged higher on Thursday after an auction of 30-year debt attracted solid demand, sending yields on 40-year JGBs down to 15-month lows.
The 40-year JGB yield fell 2 basis points to 0.835 percent, their lowest level since late December of 2016.
The 30-year JGB yield eased 1 basis point to 0.710 percent, matching a 15-month low first touched last week.
The drop in super-long bond yields came after the Finance Ministry's auction of 30-year JGBs on Thursday attracted solid demand, with the bid-to-cover ratio coming in at 4.34, exceeding 4.24 at the previous 30-year debt auction.
JGBs were mixed overall, however, with the lead June 10-year JGB futures contract falling 0.04 point to 150.95.
The benchmark 10-year JGB yield inched up 0.5 basis point to 0.030 percent. (Reporting by Tokyo markets team; Editing by Sunil Nair)