TOKYO, Oct 19 (Reuters) - Japanese government bonds were mostly little changed in thin trade on Wednesday, with the benchmark bond untraded, though prices in the superlong zone edged down slightly.
The 10-year JGB was not priced on interdealer broker JBT as of late afternoon. Its yield ended trade on Tuesday at minus 0.055 percent .
December 10-year futures ended up 0.04 point at 151.85.
The 20-year JGB yield added half a basis point (bp) to 0.395 percent, while the 30-year yield rose 1 bp to 0.505 percent.
Bank of Japan operations underpinned the market.
The central bank offered to buy 400 billion yen ($3.86 billion) of 1- to 3-year JGBs, 420 billion yen of 3- to 5-year JGBs, 190 billion yen of 10-r to 25-year JGBs and 110 billion yen of 25- to 40-year JGBs under its asset purchase programme.
Rising costs of currency hedging also underpinned JGB demand.
Hedging costs have soared on the prospect of higher interest rates and tougher U.S. money market regulations, prompting some investors to shun overseas investments in favour of the domestic bond market.
Investors awaited a 500 billion yen liquidity-enhancing auction on Thursday, under which the finance ministry regularly supplies the market with off-the-run debt. ($1 = 103.5200 yen) (Reporting by Tokyo marekts team; Editing by Kim Coghill)