TOKYO, April 4 (Reuters) - Longer-dated Japanese government bond prices gained on Wednesday on steady investor demand for debt at the start of the new domestic fiscal year.
Super-long JGB yields fell to 16-month lows amid demand from investors such as life insurers and pension funds seen to be purchasing bonds to balance their portfolios at the start of the fiscal year, which began April 1.
The 30-year yield fell 0.5 basis point to 0.710 percent, lowest since December 2016. The 40-year yield was down 1 basis point at 0.845 percent, also the lowest since December 2016.
The benchmark 10-year JGB yield edged up 1 basis point to 0.030 percent, tracking an overnight rise in U.S. Treasury yields.
As the 10-year yield nudged higher while super-long JGB yields fell, the yield curve flattened.
U.S. Treasury yields rose overnight as stock markets firmed and as investors looked ahead to Friday's closely watched employment report for March. (Reporting by the Tokyo markets team; Editing by Biju Dwarakanath)