| EST | Estimated rate. This is the value usually used to calculate accrued interest for trades settling in the current month. | |
|---|---|---|
| PAY | Paying rate, or actual rate. It is the value usually used to calculate the current month P&I payment. |
From the pool detail page, you can see historical values for both by clicking the "History" button, and then "Coupon History".
Note that only rate changes are stored in coupon history. If the EST rate does not differ from the PAY rate, we do not store it separately.