In a sign of how Treasuries' status as a global haven during times of turmoil may be fading, rates on longer-term debt soared last week as equities convulsed, turbocharging bets on a steeper yield curve.

The extra yield that investors demand to own 30-year Treasuries over two-year maturities has increased for nine straight weeks, a streak seen only one other time since Bloomberg began collating the data in 1992. Last week, that gap reached levels last seen in 2022, giving a boost to money managers such as DoubleLine that are positioned for such a move.

The appeal of long bonds dimmed last week in part on speculation that Trump's tariffs will sap international demand for Treasuries at a time when already-bloated US deficits could swell further with Congress debating tax cuts. Meanwhile, with worries around the economy growing, shorter maturities fared better versus longer-dated debt because of expectations the Federal Reserve will soon lower interest rates.