The Bank of Japan's (BOJ) massive asset purchase program has put government bond yields on a relentless slide into negative territory, and while some analysts insist a U.S. rate hike will reverse the trend later this year, others expect a slide into unchartered territory.
"Yields have fallen so low that analysts no longer have any historical risk models to fall back on," said Shinichi Tamura, Barclays' Japan bank analyst, noting that rates strategists are going on blind faith that yields will stop falling.
Japan's short-term yields, of less than three years, turned negative last year, and last week the 5-year Japanese government bond (JGB) slipped close to zero several times. As of Monday morning Asian time, the yield was quoted at 0.018 percent, up from 0.005 basis points after market close on Thursday.
Most worrying, Tamura said, is the flattening of the yield curve with long-term government bond yields also on a relentless downward trend. On Monday morning, the 10-year was quoted at 0.242 basis points -- above the historical low of 0.228 percent hit early last Friday -- and the 30-year is at 1.105 percent.
"Bond investors are uncomfortable with what they see as an abnormal situation," said Mana Nakazora, chief credit analyst at BNP Paribas. If the current levels hold, the price of new corporate bonds will be benchmarked against negative government bond yields. So, "they can't see where they are going to secure returns after 2015 and beyond, or when the BOJ will end the current round of quantitative easing and stop buying up JGBs."