Soaring U.S. debt is causing Treasury bonds to lose their risk advantage over other securities, making it more expensive to borrow money, the International Monetary Fund warned. Treasuries have long enjoyed the status as the world’s top safe haven asset. But annual budget deficits are now at $2 trillion, rapidly piling on to the $39 trillion national debt total with interest costs alone reaching $1 trillion a year. That means the Treasury Department must issue more and more fresh debt, testing the appe ...