“If the fiscal and monetary authorities won’t regulate the economy, the bond vigilantes will,” says economist Ed Yardeni on Bloomberg. ‘Bond market vigilantes’ is a term he coined in 1984 that can describe any bond-market participant (rather than an elite group of traders or fund managers).
Any bondholder may worry about whether the Federal Reserve has set interest rates too low and allowed the US government to borrow too cheaply to fund spiralling government spending. This may lead to inflation, a particular fear as it erodes a bond’s value. If enough bondholders react by selling bonds then yields will tend to rise as prices fall. This makes debt issuance more expensive for heavily indebted governments.