Japan’s 30-year government bond auction on Thursday has become a key test for global fixed-income markets as long-end yields rise worldwide. The 30-year Japanese government bond yield reached 4.155%, near its all-time high since the tenor was introduced in 1999, while the 10-year yield touched 3% for the first time this week, a three-decade record. U.S. 10-year Treasury yields climbed to 4.8% and 30-year yields to 5.28%, while German and French 30-year yields reached their highest levels since 2011. Higher oil prices linked to Middle East tensions, hawkish signals from Federal Reserve Chair Kevin Warsh at Jackson Hole and Japan’s expansionary fiscal agenda have intensified the sell-off. Bank of Japan Governor Kazuo Ueda also said a rate hike could be considered at this month’s meeting. Strategists broadly expect the auction to be average to weak, although strong demand at two comparable auctions and increased insurer purchases of super-long Japanese government bonds provide some support. Separately, an Alphaville analysis estimated that the U.S. Treasury’s yen intervention at the end of July may have totaled about $500 million, well below market expectations of $5 billion to $10 billion, though official confirmation is still pending. A weak Japanese auction could put further upward pressure on U.S. Treasury yields and raise borrowing costs worldwide.