> ## 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.

# Tranche

The **Tranche** (Underlying) refers to the tranche credit spread curves (bond and CDS) [MAR21.10](https://www.bis.org/basel_framework/chapter/MAR/21.htm?inforce=20230101\&published=20200327#paragraph_MAR_21_20230101_21_10)(2).

| Key Field                 | Key | Description                                         |
| ------------------------- | --- | --------------------------------------------------- |
| As-of Date                | Y   | Timestamp (at close of business) for the data (T-1) |
| Tranche Name (Underlying) | Y   | Name of the tranche credit spread curve             |
| Risk Class                | Y   | “CSR Sec non-CTP”                                   |
| Bucket                    |     | 1-25                                                |
| Credit Quality            |     | e.g. “Senior IG”, “IG”, “HY”, or “NR”               |
| Sector                    |     | The relevant sector of the asset pool               |
| Pool                      |     | The asset pool                                      |
| Attachment                |     | The attachment point of the tranche in the pool     |
| Detachment                |     | The detachment point of the tranche in the pool     |