Investment Grade (IG)

Credit-rating agencies assess the financial strength of bond issuers and assign letter-grade ratings. Investment grade encompasses the upper rating categories — commonly summarized as ratings at or above a specific threshold set by the major agencies — while bonds rated below that threshold are often called "high yield" or, informally, "junk bonds." The distinction matters because many institutional investors, pension funds, and endowments are restricted by policy or regulation to holding only investment-grade bonds, which influences demand and liquidity for those securities.

For families, the IG label is a starting point for evaluating credit quality, not a guarantee of safety. Even highly rated bonds can be downgraded — a "fallen angel" is a bond that slips from investment grade to high yield — and downgrades can trigger forced selling by institutions that must maintain IG-only portfolios, sometimes depressing prices sharply. Understanding the credit spread associated with a particular IG bond provides a more nuanced picture of how the market actually prices its risk.

A common confusion is treating all investment-grade bonds as interchangeable. The IG band spans a wide range of credit quality: a bond at the top of the ratings scale is meaningfully different from one sitting just at the IG threshold. Families evaluating corporate bonds or municipal bonds may find it useful to look within the IG category at individual ratings tiers, not simply at whether a bond qualifies as investment grade at all.