Investment grade
The boundary below which an issue counts as speculative; it decides who is permitted to hold the bond at all.
How to read the number
The line matters because of mandates: some managers are obliged to sell an issue that drops below it, whatever they think of the issuer.
When the metric lies
Forced selling arrives in a short burst and presses the price harder than the deterioration warrants. A fall on a downgrade often says more about mandates than about default probability.
Also known as: investment category, above the speculative line