The fear of a global bond bubble bursting has the market on edge, but it takes a brave investor to bet against a rally that smashed so many records.
Instead, those seeking to guard against a sell-off are favoring less direct ways — shifting into shorter-dated debt that's less vulnerable to price swings, buying bearish options and boosting holdings of high-quality credit. Such trades represent a wager that the global economic pessimism, which has been driving the fixed-income surge, is somewhat exaggerated and that inflation still has a chance of picking up.
This year's unprecedented rally has pushed yields on more than $17 trillion of global debt below zero, with Germany's entire curve now negative. While that means buyers are guaranteed to take a loss if they hold the securities to maturity, many are still piling in on the hope of price gains, prompting some investors to warn that a bond bubble may be in the making.
"There is a significant risk of a sell-off at the moment," said Luke Hickmore, a money manager at Aberdeen Standard Investments. "A big sell-off would occur if the big global risks — the trade war or Brexit — ease off or central banks underwhelm with their policy response."
Yields have risen as a number of risks — from Brexit to Italian and Hong Kong politics — all eased at the same time, while traders pare back bets on fresh bond-buying from the European Central Bank next week.
Thirty-year German yields have rebounded almost 25 basis points from a record low of -0.31% reached in mid-August, with the premium over five-year bonds at its highest in over a month. Similar rates in the U.S. have climbed back above 2% from an all-time low of 1.9% last week.
The concern that the bond rally may lose steam is also being fueled by the prospect of governments stepping up fiscal spending — a move that would entail increased debt supply that would weigh on fixed-income prices. Germany is said to be considering boosting budget support to its struggling economy.
"We know not the day or the hour, but risks for bonds are mounting and it is time to cover longs," Societe Generale strategists led by Subadra Rajappa wrote in a note. German 10-year yields, which are close to a record low of -0.74% reached Tuesday, are about 25 basis points too low, according to the bank. "Bonds are pricing in significant uncertainty premium and policy accommodation, and are vulnerable to a sell-off."
Investors may also be looking to lock in profits after investment-grade bonds have returned nearly 8% this year, according to Bloomberg Barclays Indices.