> ## 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. # UnderlyingDescription The **UnderlyingDescription** store contains the description of the principal component of the risk-factors. It is indexed by **Underlying**, **RiskClass**, and **AsOfDate** and referenced from the [RiskFactorDescription](./risk-factor-desc) store by these three fields. The fields used in this store, and their purpose, depends on the risk-class. See the [Implementation and Interpretation Guide](../../interpret-impl/acr/sa/sa-sbm/index) for details on each risk-class. Each row in the store will describe one of the following depending on the risk class: | Risk Class | Underlying | | -------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- | | (link to risk-class specific use of this store) | (link to risk-class specific data model) | | [GIRR](../../interpret-impl/acr/sa/sa-sbm/girr/datastore-ref-impl/underlying-desc) | [yield, inflation, or cross-currency basis curve](../../interpret-impl/acr/sa/sa-sbm/girr/data-model-core/index) | | [FX](../../interpret-impl/acr/sa/sa-sbm/fx/datastore-ref-impl/underlying-desc) | [FX rate](../../interpret-impl/acr/sa/sa-sbm/fx/data-model-core/index) | | [Equity](../../interpret-impl/acr/sa/sa-sbm/equity/datastore-ref-impl/underlying-desc) | [equity or equity issuer](../../interpret-impl/acr/sa/sa-sbm/equity/data-model-core/index) | | [CSR non-Sec](../../interpret-impl/acr/sa/sa-sbm/csr-non-sec/datastore-ref-impl/underlying-desc) | [relevant issuer credit spread curve](../../interpret-impl/acr/sa/sa-sbm/csr-non-sec/data-model-core/index) | | [CSR Sec non-CTP](../../interpret-impl/acr/sa/sa-sbm/csr-sec-non-ctp/datastore-ref-impl/underlying-desc) | [tranche credit spread curves](../../interpret-impl/acr/sa/sa-sbm/csr-sec-non-ctp/data-model-core/index) | | [CSR Sec CTP](../../interpret-impl/acr/sa/sa-sbm/csr-sec-ctp/datastore-ref-impl/underlying-desc) | [underlying credit spread curves](../../interpret-impl/acr/sa/sa-sbm/csr-sec-ctp/data-model-core/index) | | [Commodity](../../interpret-impl/acr/sa/sa-sbm/commodity/datastore-ref-impl/underlying-desc) | [distinct commodity](../../interpret-impl/acr/sa/sa-sbm/commodity/data-model-core/index) | | [Crypto 2a](../../interpret-impl/acr/sa/sa-sbm/crypto-2a/datastore-ref-impl/underlying-desc) | [crypto 2a underlying](../../interpret-impl/acr/sa/sa-sbm/crypto-2a/data-model-core/index) | | Store Field | Key | CanBeNull | Type | Cube Field | Description | | ----------------------- | --- | --------- | ---------------------- | ------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------ | | Underlying | Y | | String | [Underlying](../../cube/underlying) | The primary component of the risk factor. | | RiskClass | Y | | String | See field in referencing store ([RiskFactorDescription](./risk-factor-desc)) | The risk-class ("GIRR", "CSR non-Sec", "CSR Sec non-CTP", "CSR Sec CTP", "Equity", "Commodity", "FX", "Crypto 2a") | | Bucket | | Y | String | \[Buckets].\[\<*SBM risk class*> Buckets]
For example [Equity Buckets](../../cube/equity-buckets) | The Bucket the Underlying belongs to. | | GIRR Curve Type | | Y | String | [GIRR Curve Types](../../cube/girr-curve-types) | GIRR Delta and Vega only. The Curve type (“Yield”, “Basis”, or “Inflation”) | | GIRR Ccy | | Y | String | [Currencies](../../cube/currencies) | GIRR only. The currency of the curve. This is also the Bucket. | | CSRQuality | | Y | String | [CSR Quality](../../cube/csr-quality) | CSR only. The credit quality of the curve ("Senior IG", IG", "HY", or "NR") | | CSRSector | | Y | String | [CSR Sector](../../cube/csr-sector) | CSR only. The relevant sector of the curve | | CSRRating | | Y | String | [CSR Rating](../../cube/csr-rating) | CSR non-Sec only. "high" for AA- and above covered bonds. | | Pool | | Y | String | [CSR Sec non-CTP Pool](../../cube/csr-sec-non-ctp-pool) | CSR Sec non-CTP only. Underlying pool for the tranche | | Attachment | | Y | Double | [CSR Sec non-CTP Attachment](../../cube/csr-sec-non-ctp-attachment) | CSR Sec non-CTP only. Attachment point for the tranche. | | Detachment | | Y | Double | [CSR Sec non-CTP Detachment](../../cube/csr-sec-non-ctp-detachment) | CSR Sec non-CTP only. Detachment point for the tranche | | EquityMarketCap | | Y | String | [Equity Market Cap](../../cube/equity-market-cap) | Equity only. The equity issuer market cap ("Large", "Small", "Other") | | EquityEconomy | | Y | String | [Equity Issuer Economy](../../cube/equity-issuer-economy) | Equity only. The equity issuer economy ("Emerging", "Advanced", "Other") | | EquitySector | | Y | String | [Equity Sector](../../cube/equity-sector) | Equity only. The equity issuer sector. | | UnderlyingFXOriginalCcy | | Y | String | FX Original Bucket (This is an internal field) | | | GIRR Basis Ccy | | Y | String | [Girr Basis Ccy](../../cube/girr-basis-ccy) | GIRR only. The counter currency for GIRR cross-currency basis curves (USD or EUR). | | AsOfDate | Y | | LOCALDATE\[yyyy-mm-dd] | See field in referencing store ([SaSensitivities](./sa-sensitivities)) | Timestamp (at close of business) for the data. | | Crypto2aExchange | | Y | String | [Crypto 2a Exchange](../../cube/crypto-2a-exchange) | Optional field. Disabled by default. See [Crypto 2a UnderlyingDescription](../../interpret-impl/acr/sa/sa-sbm/crypto-2a/datastore-ref-impl/underlying-desc). | References to bucket description stores: | Risk Class | Fields Used in Reference | Bucket Store | | ----------------------------------------- | --------------------------------------- | ---------------------------------------- | | Equity | **AsOfDate**, **Bucket**, **RiskClass** | [EquityBucketDesc](./equity-bucket-desc) | | CSR non-Sec, CSR Sec non-CTP, CSR Sec CTP | **AsOfDate**, **Bucket**, **RiskClass** | [CSRBucketDesc](./csr-bucket-desc) |