Identified mortgage pool named for delivery or analysis instead of traded only through a generic TBA description.
A specified pool is an identified mortgage pool named for delivery or analysis instead of traded only through a generic to-be-announced description.
Specified pool matters because the mortgage-backed securities market often begins with broad pool characteristics, then eventually needs actual pool details. A specific group of loans can have traits that investors value differently from a generic pool.
It also matters because borrowers sometimes hear that mortgage pricing is tied to the MBS market without understanding that the market looks at grouped loan characteristics. Pools can differ by loan size, geography, age, coupon, prepayment behavior, and other mortgage-specific features.
Borrowers rarely see specified-pool language directly. It appears behind the scenes after loans close, when eligible mortgages are pooled, delivered, traded, or analyzed in the secondary market.
The term becomes practical when explaining how a lender moves from a locked borrower pipeline into agency MBS delivery and why not every pool with the same broad coupon trades exactly the same way.
| Market label | What it tells the reader |
|---|---|
| To-Be-Announced Market | Broad agency MBS trade before exact pools are named |
| Specified pool | Actual pool identified by pool-level characteristics |
| Mortgage Pool | Group of loans behind a security |
| Pool Factor | How much of the original pool balance remains |
A trade may begin as a generic agency MBS transaction. Later, the seller identifies the actual pool that meets the trade requirements. Once the pool is named and evaluated by its own characteristics, it is being treated as a specified pool.
Specified pool differs from Mortgage Pool because mortgage pool is the general group of loans, while specified pool emphasizes that the actual pool has been identified for trading, delivery, or analysis.
It differs from the To-Be-Announced Market because TBA trading starts from generic delivery terms, while specified-pool analysis focuses on named pool characteristics.
It also differs from MBS Price because specified pool is the identified collateral pool, while MBS price is the market value at which the security or pool trades.