> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Underlying

The **Underlying** refers to the underlying credit spread curves (bond and CDS) [MAR21.11](https://www.bis.org/basel_framework/chapter/MAR/21.htm?inforce=20230101\&published=20200327#paragraph_MAR_21_20230101_21_11)(2).

| Field           | Key | Description                                         |
| --------------- | --- | --------------------------------------------------- |
| As-of Date      | Y   | Timestamp (at close of business) for the data (T-1) |
| Underlying Name | Y   | Name of the underlying                              |
| Risk Class      | Y   | “CSR Sec CTP”                                       |
| Bucket          |     | 1-16                                                |
| Credit Quality  |     | “IG”, “HY”, or “NR”                                 |
| Sector          |     | The relevant sector of the underlying               |