TOKYO, Oct 11 (Reuters) - Longer-dated Japanese government bonds slumped on Thursday ahead of a 30-year sale that was expected to meet firm demand in light of that sector's recent underperformance.
* The Ministry of Finance is offering 700 billion yen ($8.9 billion) of 30-year bonds with a coupon of 1.90 percent, matching that of the previous sale, which had drawn decent demand.
* "We are not expecting an eventful auction," said a fixed-income fund manager at a Japanese asset management firm.
"It would be very surprising if there was little demand at these levels, after superlongs have underperformed in recent weeks," he said.
* The yield curve has steepened this week ahead of the auction as investors sold to make room in their portfolios to buy at the auction.
The spread between the 10-year and 30-year yields rose to 1.17 percentage points on Thursday, its widest since March 2008.
* Yields on 30-year debt rose 1.5 basis points in cash trading to 1.940 percent, while those on 20-year bonds rose half a basis point to 1.660 percent.
* The benchmark 10-year yield was flat at0.765 percent.
* Ten-year JGB futures ended morning trade up 0.03 point at 144.21, after trading in a narrow range between 144.19 and 144.24.
If futures' five-day moving average were to cross below the 200-day moving average, that might be a bearish technical signal. The five-day average is now at 144.16 and the 200-day average is at 144.12.
* "We continue to recommend buying 30-year asset swaps, which remain attractively cheap and appear likely to outperform in the event of JGB market selloffs," Morgan Stanley MUFG strategists said in a note to clients ahead of the 30-year sale.
They added that 30-year asset swaps offer around 1 basis point of carry over a half-year period, which would make them suitable for bearish positioning in the longer term.
($1 = 78.085 Japanese yen)
(Reporting by Lisa Twaronite; Editing by Chris Gallagher)
Keywords: MARKETS JAPAN JGB/