U.S. Mortgage Index

RSSD ID

Also called ID_RSSD

Definition

An RSSD ID, also called ID_RSSD, is a unique identifier the Federal Reserve assigns to an entity in its structure database. It labels the entity. It does not, by itself, say what the entity is, and it is not a claim that every mortgage lender has one.

In plain English

When this site or a researcher talks about an RSSD ID, they mean a file key: a number that points to one entity in Federal Reserve records. That is a different job from an NMLS ID, a Legal Entity Identifier, an FDIC certificate number, or an NCUA charter number. This page does not invent a phrase for what “RSSD” stands for. Official materials used here call it RSSD ID or ID_RSSD.

Technical definition

The Federal Reserve Micro Data Reference Manual (item 9001) describes ID_RSSD as the primary identifier on the database: a unique one-up number with a check digit, assigned when an entity is first added, carrying no inherent attribute information, never changing, and never reused. The identifier persists after an entity is liquidated or permanently closed. FFIEC NIC public help pages remain unread; this freeze does not invent NIC operating instructions.

Why it matters

Banking-structure data key on RSSD. The identity layer needs that key named correctly so it is not treated as a consumer license number.

Example

Two distinct entities represented in the Federal Reserve database have distinct RSSD IDs. The numbers identify the records. They do not encode what kind of institution either entity is.

Commonly confused with

Sources reviewed

Important note

This page does not expand the letters “RSSD,” does not treat the identifier as a type code, and does not say every mortgage lender has an RSSD ID.

Last reviewed

September 4, 2026