> ## Documentation Index
> Fetch the complete documentation index at: https://docs.creditbenchmark.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Credit Benchmark Rating Scale
> Credit Benchmark maps Probability of Default values to Consensus Credit Ratings through its standardized 21-category scale, from aaa through d.
This page explains how Credit Benchmark maps Probability of Default (PD) values to Consensus Credit Ratings (CCR) through its standardized 21-category scale. If you are new to Credit Benchmark, start with the [CCR overview](/methodology/consensus-credit-rating).
## Credit Benchmark Rating Scale
Credit Benchmark's rating scale provides a standardized way to translate Probabilities of Default (PDs) into a credit rating. The scale ranges from **aaa** (highest credit quality) to **d** (default).
Our scale is a consensus construct derived from the PD scales of **40+ banks**. Each bank maintains its own master scale, including PD cutoffs for each internal grade. We aggregate those PD cutoffs across contributors and interpolate a single set of lower and upper through-the-cycle (TTC) PD boundaries for each category in the Credit Benchmark 21-category scale.
These boundaries are:
* **Aggregated from multiple independent sources** - A true consensus, not a vendor opinion
* **Expressed as annual TTC PD ranges** - To reduce procyclicality
* **Reviewed periodically** - To maintain stability and comparability across sectors, regions, and size buckets
### Rating Categories and PD Mappings
All PD bounds are expressed in basis points (bps). For example, 30 bps = 0.30%.
| Notch | Rating | PD Lower (bps) | PD Upper (bps) | Category |
| ----- | -------- | -------------- | -------------- | -------- |
| 1 | **aaa** | 0 | 1.25 | IG |
| 2 | **aa+** | 1.25 | 2.25 | IG |
| 3 | **aa** | 2.25 | 3.25 | IG |
| 4 | **aa-** | 3.25 | 4.75 | IG |
| 5 | **a+** | 4.75 | 6.25 | IG |
| 6 | **a** | 6.25 | 8.5 | IG |
| 7 | **a-** | 8.5 | 14 | IG |
| 8 | **bbb+** | 14 | 20 | IG |
| 9 | **bbb** | 20 | 30 | IG |
| 10 | **bbb-** | 30 | 48 | IG |
| 11 | **bb+** | 48 | 76 | HY |
| 12 | **bb** | 76 | 112 | HY |
| 13 | **bb-** | 112 | 195 | HY |
| 14 | **b+** | 195 | 365 | HY |
| 15 | **b** | 365 | 650 | HY |
| 16 | **b-** | 650 | 1000 | HY |
| 17 | **ccc+** | 1000 | 1700 | HY |
| 18 | **ccc** | 1700 | 2500 | HY |
| 19 | **ccc-** | 2500 | 3700 | HY |
| 20 | **cc** | 3700 | 6800 | HY |
| 21 | **c** | 6800 | 10000 | HY |
| — | **d** | — | — | Default |
Credit Benchmark also maintains a secondary `CCR100` scale for finer PD-based granularity in some published fields. The headline CCR continues to use the 21-category scale. See [Consensus PD](/methodology/consensus-pd) for how `CCR100` fields are published.
## How We Create the Consensus Scale
Credit Benchmark's PD scale represents the collective wisdom of **40+ leading global banks**. Each bank has its own internal rating system with unique naming conventions and PD boundaries. Our challenge is to harmonize these disparate systems into a single, standardized consensus scale.
### The Challenge: Multiple Rating Systems
Each contributor bank has its own internal rating system with unique naming conventions:
| Bank Type | Example Rating System |
| -------------------- | ------------------------------------- |
| **European Bank** | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 |
| **US Regional Bank** | A1, A2, A3, B1, B2, B3, C1, C2, C3, D |
| **Asian Bank** | AAA, AA, A, BBB, BB, B, CCC, CC, C, D |
### The Solution: Standardization Process
We create a consensus definition of what PD maps to each credit grade by using each bank's internally assigned **Credit Rating Agency Equivalent** (e.g., S\&P, Moody's, Fitch) as our common language. This allows us to compare like-for-like credit quality across different internal scales.
Each bank provides us with its internal rating definitions and how they map to standard credit rating agency equivalents. For example:
* **European Bank's 6** -> Equivalent to S\&P BBB
* **US Regional Bank's B1** -> Equivalent to S\&P BBB
* **Asian Bank's BBB** -> Equivalent to S\&P BBB
This common reference point allows us to compare PD estimates across different internal rating systems.
For each S\&P equivalent rating (e.g., **BBB**), we collect the PD values from all banks and analyze the lower, midpoint, and upper boundaries contributed across the network. For example:
* **European Bank** (Grade 6) — 17–32 bps, midpoint 23 bps
* **US Regional Bank** (B1) — 19–34 bps, midpoint 25 bps
* **Asian Bank** (BBB) — 18–31 bps, midpoint 24 bps
*Example data for illustration. Actual contributor values are confidential.*
Aggregating across all contributors for this grade produces the Consensus PD range used in Step 3.
We analyze the PD distributions across all banks for each rating category and calculate the consensus boundaries:
* **BBB consensus range**: 20-30 basis points
* **BBB midpoint**: 25 basis points
* This becomes our **bbb** rating range in the Credit Benchmark scale
The process is repeated for each rating category to create the full Credit Benchmark 21-category rating scale.
## Annual Review and Alignment
Our PD mapping table is evaluated periodically to ensure boundaries remain aligned with the consensus across all contributor banks. This review process maintains the scale's accuracy and relevance as bank risk models and market conditions evolve.
For a deeper discussion of how our consensus ratings compare with S\&P and Fitch, see [Alignment with Rating Agencies](./rating-agency-alignment).