Issuer Credit Ratings: Scales, Factors, and Agencies

An issuer credit rating is a credit rating agency’s forward-looking opinion of an organization’s overall ability and willingness to pay its financial obligations on time.¹ It applies to the entity as a whole rather than to any single bond or loan, and it is expressed as a letter grade that tells lenders, investors, and counterparties how likely the borrower is to default. The difference between a strong rating and a weak one can translate into millions of dollars a year in interest costs.

Issuer Rating Versus Issue Rating

An issuer credit rating looks at general creditworthiness. It ignores collateral, seniority, guarantees, and other features that could make one specific debt safer than another.¹

An issue rating evaluates one specific obligation. It factors in whether the bond is secured, where it sits in the repayment line in bankruptcy, and whether a third party guarantees it. A single company can carry an issue rating on its senior secured debt above its issuer rating, and an issue rating on its subordinated unsecured debt below it. The issuer rating is the anchor; issue ratings move up or down from there.

How to Read the Rating Scales

Each major agency uses its own symbols, but the scales line up closely. The key dividing line is between investment grade (relatively low default risk) and speculative grade, often called high-yield or junk.

Long-Term Ratings

S&P and Fitch use identical letters. Their scale runs AAA, AA, A, BBB, BB, B, CCC, CC, C, and D (default). Everything at BBB- or above is investment grade; BB+ and below is speculative.² A plus or minus sign shows where an issuer sits within a letter category: A+ is at the top of the A band, A- is at the bottom.

Moody’s uses a different convention with the same logic. Its scale runs Aaa, Aa, A, Baa, Ba, B, Caa, Ca, and C. Investment grade extends down to Baa3; speculative grade begins at Ba1. Within each category, Moody’s appends 1 (strongest), 2 (middle), or 3 (weakest).³

The scales align at key thresholds:

Highest quality: S&P/Fitch AAA, Moody’s Aaa
Lowest investment grade: S&P/Fitch BBB-, Moody’s Baa3
Highest speculative grade: S&P/Fitch BB+, Moody’s Ba1
Near default: S&P/Fitch CCC, Moody’s Caa

Short-Term Ratings

Short-term ratings cover obligations maturing within about a year and matter most for commercial paper. S&P’s short-term scale runs A-1+, A-1, A-2, A-3, B, C, and D.¹ Moody’s uses Prime ratings: P-1 (superior), P-2 (strong), P-3 (acceptable), and NP (not prime).³ An issuer can carry a solid short-term rating on the strength of immediate liquidity while holding a weaker long-term rating if the multi-year picture is less certain.

What the Letters Have Historically Meant for Default

Ratings are opinions, not guarantees, but the historical record shows a strong relationship between rating and default risk. S&P’s 2025 annual default study, covering 1981 through early 2025, found that no AAA- or AA-rated corporate issuer has ever defaulted within one year of holding that rating. The weighted long-term average one-year default rate is 0.04% for A-rated issuers, 0.13% for BBB, and 0.55% for BB.⁴

The curve steepens sharply at the bottom. B-rated issuers default at an average annual rate of 2.87%, and CCC/C-rated issuers default at 26.12% per year.⁴ Roughly one in four CCC-or-below issuers defaults within a single year.

Outlooks and CreditWatch

A rating isn’t a static grade. Agencies attach forward-looking signals that tell the market whether a change may be coming.

A credit outlook reflects where the agency thinks the rating could move over the medium term. S&P uses four labels: positive, negative, stable, and developing (when the direction depends on an unresolved event). The outlook window extends up to two years for investment-grade issuers and roughly one year for speculative-grade issuers. S&P assigns an outlook when it sees at least a one-in-three chance of a rating change in that window.⁵ Moody’s uses the same four categories.³

When a specific event raises the possibility of a rating change more urgently, agencies escalate. S&P calls this CreditWatch; Moody’s calls it review for upgrade or review for downgrade. A CreditWatch listing signals at least a one-in-two chance of an action within 90 days, though it can run longer if the triggering event stays unresolved. While an issuer is on CreditWatch, the outlook is suspended.⁵ Typical triggers include announced mergers, surprise regulatory actions, and sudden financial deterioration. A watch listing doesn’t guarantee a downgrade, but it concentrates attention quickly and can widen borrowing spreads before the agency acts.

What Goes Into the Rating

Analysts build a composite picture from financial data and qualitative judgment. The process involves public filings, direct meetings with management, and stress-testing the business against different economic scenarios.²

Financial Metrics

Analysts start with audited financials, particularly the 10-K and 10-Q filings public companies submit to the SEC. They focus on leverage (debt relative to equity and earnings), cash flow coverage (whether operating cash flow comfortably covers interest), and liquidity (whether short-term assets can meet short-term obligations). A company producing steady, predictable cash flow earns more tolerance for leverage than one with volatile earnings, even at similar raw debt levels.

Business Profile and Industry Position

The numbers don’t stand alone. Analysts weigh competitive position: pricing power, revenue diversification, and whether the industry itself is growing or shrinking. A dominant firm in a stable industry starts stronger than one in a fragmented, cyclical market. Regulatory risk also matters, since rule changes in a heavily regulated sector can suddenly raise costs or restrict operations.

Management and Governance

Analysts talk directly with management to gauge strategy, financial policy, and approach to risk.² A team with a record of conservative financial decisions and transparent communication tends to earn more favorable treatment than one with aggressive leverage or opaque reporting. Board independence and compensation structures feed into this assessment.

ESG Where It Is Material

ESG considerations have entered the analysis, though the role is narrower than headlines suggest. Fitch incorporates environmental, social, and governance factors only when they are materially relevant to a specific rating, publishing ESG relevance scores alongside the rating to show how those factors influenced the outcome rather than treating the scores themselves as a direct input.⁶ A coal miner might see environmental risk flagged as material; a software firm likely would not.

Why the Investment-Grade Line Matters So Much

The boundary between investment grade and speculative grade is more than a label. Many pension funds, insurance companies, and other institutional investors are restricted by their mandates or regulations from holding speculative-grade debt. When an issuer slips from BBB- (or Baa3) to BB+ (or Ba1), it crosses that line, and the consequences cascade.

Issuers that cross downward are called fallen angels. Forced selling from portfolios that can no longer hold the bonds can push prices down and lift the issuer’s borrowing cost. The reverse move, from BB+ up to BBB-, makes an issuer a rising star and opens access to a far larger pool of investors.

Loan agreements and bond indentures often contain rating triggers that activate if the issuer falls below a specified threshold. These clauses can require additional collateral, higher interest rates, or accelerated repayment. For a company already stressed, a trigger demanding early repayment can turn a downgrade into a liquidity crisis. That is one reason analysts and investors watch not only the current rating but the outlook and any CreditWatch status.

Who Issues These Ratings

Three firms dominate: S&P Global Ratings, Moody’s Investors Service, and Fitch Ratings. They are not the only players. The SEC currently recognizes 11 firms as Nationally Recognized Statistical Rating Organizations, including A.M. Best (insurance-focused), DBRS, Kroll Bond Rating Agency, and Egan-Jones.⁷

The NRSRO designation matters because many federal regulations, investment mandates, and bank capital rules reference ratings from recognized agencies. The SEC’s Office of Credit Ratings examines registered agencies and monitors compliance, but it cannot regulate the substance of ratings or dictate methodologies.⁸

Who Pays, and Why It Matters

Under the issuer-pay model used by the three dominant agencies, the company being rated writes the check. The conflict is straightforward: an agency paid by the issuer faces commercial pressure to keep that client. Issuers can shop among agencies for the most favorable grade, agencies that sell advisory services alongside ratings can develop relationships that compromise objectivity, and issuers can sometimes decline to publish a rating they don’t like, so the market only sees the better outcome.

The SEC has brought enforcement actions on these conflicts, and reforms under Dodd-Frank pushed agencies to strengthen internal firewalls around conflicts and methodology transparency.⁹ The underlying economics of the issuer-pay model remain in place. When reading a rating, it is worth knowing who paid for it.

Unsolicited, Municipal, and Sovereign Ratings

Not every rating is requested by the issuer. Agencies also publish unsolicited ratings, assigned without the issuer’s participation or payment. The SEC has flagged concerns about this practice, including cases where agencies sent invoices for unsolicited ratings or implied that cooperation might improve the outcome.¹⁰ Current rules require agencies to identify an unsolicited rating as such. The rating isn’t necessarily less accurate, but it is built from public information alone rather than the direct management access that typically informs a solicited one.

Corporate ratings aren’t the only kind. State and local government issuers are assessed on the local tax base, economic diversity, pension funding, demographics, and the legal structure backing the debt; a general obligation bond backed by full taxing authority is evaluated differently than a revenue bond backed only by income from a toll road or water system. Sovereign ratings on national governments add factors like monetary policy flexibility, the currency in which debt is denominated, political stability, and external debt. A sovereign rating often serves as a ceiling for corporate issuers in the same country, though some companies with diversified international operations or strategic importance can be rated above their home sovereign under specific criteria.

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S&P Global Ratings. S&P Global Ratings Definitions
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S&P Global Ratings. Understanding Credit Ratings
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Moody’s. Rating Symbols and Definitions
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S&P Global Ratings. Default, Transition, and Recovery: 2025 Annual Global Corporate Default and Rating Transition Study
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S&P Global Ratings. General Criteria: Use of CreditWatch and Outlooks
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Fitch Ratings. Fitch Ratings Publishes General ESG Approach
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U.S. Securities and Exchange Commission. Current NRSROs
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U.S. Securities and Exchange Commission. Credit Rating Agency Reform Act of 2006Office of Credit Ratings
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U.S. Securities and Exchange Commission. Learn More About NRSROs
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U.S. Securities and Exchange Commission. Rating Agencies and the Use of Credit Ratings Under the Federal Securities Laws