TOKYO, April 26 (Reuters) - Japanese government bond prices were weighed down as an ebb in risk aversion sent Tokyo stocks to four-week highs and weakened investor demand for safe-haven debt.
An overnight retreat by U.S. Treasuries also hurt JGBs, although the Bank of Japan conducted a regular bond-buying operation and helped limit the bond market's losses.
The benchmark 10-year JGB yield was half a basis point higher at 0.020 percent and the 20-year yield rose 1.5 basis points to 0.570 percent.
As part of its regular debt-buying programme, the BOJ on Tuesday bought a total of 750 billion yen ($6.75 billion) of JGBs ranging in maturities from five years to those exceeding 25 years.
The Nikkei rose to the four-week peak on Wednesday, buoyed by a weaker yen and record high for the Nasdaq Composite.
U.S. Treasuries fell overnight as Wall Street stocks rose and as investors awaited President Donald Trump's announcement on tax reform on Wednesday. ($1 = 111.1900 yen) (Reporting by the Tokyo markets team; Editing by Sam Holmes)