What Is an Investment Grade Rating?
An investment grade rating is a credit rating of BBB‑ or higher from S&P Global or Fitch, or Baa3 or higher from Moody’s, indicating a relatively low risk of default. The scale contains exactly ten investment grade notches, from AAA at the top down to BBB‑ at the cutoff line. Everything below that line — BB+/Ba1 and lower — is speculative grade, commonly called high yield or junk. The distinction is not cosmetic: over the 1981–2024 period studied by S&P Global, the 10‑year cumulative default rate was 4.40% for BBB‑rated issuers versus 14.53% for BB‑rated issuers — more than a threefold jump across a single rating tier.
The same threshold drives decisions far beyond the bond market. Index eligibility, bank and insurance capital charges, counterparty requirements, and investment grade credit tenant lease underwriting in net lease real estate all key off the BBB‑/Baa3 line.
Investment Grade Rating Scale: S&P, Moody’s and Fitch
All three major agencies use a letter scale, but Moody’s notation differs from S&P and Fitch. This table maps every notch and shows exactly where investment grade ends.
| S&P / Fitch | Moody’s | Tier | Investment Grade? |
|---|---|---|---|
| AAA | Aaa | Prime | Yes |
| AA+ / AA / AA‑ | Aa1 / Aa2 / Aa3 | High grade | Yes |
| A+ / A / A‑ | A1 / A2 / A3 | Upper medium grade | Yes |
| BBB+ / BBB | Baa1 / Baa2 | Lower medium grade | Yes |
| BBB‑ | Baa3 | Lowest investment grade | Yes — the cutoff |
| BB+ / BB / BB‑ | Ba1 / Ba2 / Ba3 | Speculative | No |
| B+ / B / B‑ | B1 / B2 / B3 | Highly speculative | No |
| CCC / CC / C | Caa / Ca / C | Substantial risk | No |
| D | — | In default | No |
Sources: S&P Global Ratings, Moody’s Ratings, Fitch Ratings rating definitions. For notch‑by‑notch verdicts (is Baa3 investment grade, is Baa2 investment grade, is Ba1 investment grade), see our bond ratings scale guide.
Where Is the Investment Grade Cutoff?
The cutoff is BBB‑ at S&P and Fitch, and Baa3 at Moody’s. A single downgrade from BBB‑/Baa3 pushes an issuer into high yield territory — the so‑called “fallen angel” event. Because many mandates, index rules, and capital regulations only permit investment grade holdings, crossing that line can force selling by insurance companies, pension funds, and bond index funds regardless of the manager’s own view of the credit.
When agencies disagree — for example, Baa3 from Moody’s but BB+ from S&P — the bond is a “crossover” or split‑rated credit. Index providers resolve splits with their own rules: some use the middle rating of three, others the lower of two. That is why an issuer can sit in an investment grade index at one provider and a high yield index at another at the same time.
The BBB tier dominates the market. BBB rated issuers (BBB+, BBB, BBB‑) account for roughly half of the U.S. investment grade corporate bond market, which is why the health of the BBB tier — and the distance to the cutoff — is the single most watched risk metric in investment grade bonds.
Who Assigns Investment Grade Ratings?
The three dominant Nationally Recognized Statistical Rating Organizations (NRSROs) are S&P Global Ratings, Moody’s Ratings, and Fitch Ratings. Each publishes long‑term issuer and issue ratings based on leverage, cash flow coverage, business risk, industry position, and financial policy. A rating is an opinion about relative default risk — not a buy or sell recommendation, and not a guarantee. Agencies also attach outlooks (positive, stable, negative) and watch listings that signal the likely direction of the next rating action.
For a plain‑English walkthrough of how the entire framework works across bonds, tenants, and real estate, start with our investment grade guide.
Why an Investment Grade Rating Matters
Three practical consequences follow from the rating line. First, borrowing cost: investment grade issuers fund materially cheaper than high yield issuers, and the spread between the two tiers widens sharply in risk‑off markets (see our investment grade vs high yield comparison). Second, market access: commercial paper programs, certain derivative counterparties, and many institutional mandates are only available to investment grade credits. Third, regulatory treatment: bank risk weights and insurance capital charges step up materially below the cutoff, which shrinks the natural buyer base for speculative grade paper.
The same line prices real estate. In net lease investing, a property leased to an investment grade rated tenant is a credit instrument wrapped in real estate: the corporate guarantee behind the lease is underwritten with the same BBB‑/Baa3 framework used for bonds — typically at a 100–250 bps cap rate premium to the same company’s bond yield. See the current ratings for 180+ net lease tenants in our credit tenant ratings table.
Investment Grade Rating FAQ
What is the lowest investment grade rating?
BBB‑ from S&P Global or Fitch, and Baa3 from Moody’s, are the lowest investment grade ratings. One notch lower — BB+ or Ba1 — is speculative grade (high yield).
Is BBB‑ a good credit rating?
BBB‑ is the lowest rung of investment grade. It signals adequate capacity to meet obligations, but with more sensitivity to adverse economic conditions than higher ratings. Historically, BBB tier issuers defaulted at a 4.40% cumulative rate over 10 years (S&P, 1981–2024) — low in absolute terms, but the highest within investment grade.
Is Baa3 investment grade?
Yes. Baa3 is Moody’s lowest investment grade rating, equivalent to BBB‑ at S&P and Fitch. The next notch down, Ba1, is not investment grade.
How many investment grade ratings are there?
Ten notches: AAA, AA+, AA, AA‑, A+, A, A‑, BBB+, BBB, and BBB‑ (Aaa through Baa3 in Moody’s notation).
What is a fallen angel?
A fallen angel is a bond or issuer downgraded from investment grade (BBB‑/Baa3 or above) to speculative grade (BB+/Ba1 or below). The downgrade often triggers forced selling by funds and institutions restricted to investment grade holdings.
Do investment grade ratings apply to real estate?
Indirectly, yes. In net lease (NNN) real estate, properties leased to tenants whose corporate credit is rated BBB‑/Baa3 or better are called investment grade credit tenant properties. Lenders and buyers underwrite the lease using the tenant’s bond rating, so the same cutoff that governs bonds also drives NNN cap rates and financing terms.
