a. retrieving specifications of aspects of a plurality of assets, said assets generating cashflows from payment by obligors of principal and interest, wherein a level of the cashflows generated from said assets changes due to prepayments by said obligors;

b. retrieving a specification of the asset-backed security created from said plurality of assets;

c. determining, by execution of the program instructions in the processor, from said specifications of said aspects of the plurality of assets and said specification of said asset-backed security, a schedule of future cashflows that will be generated from the assets based on at least one of principal payments and interest payments from said obligors whose assets are members of said asset pool;

d. modeling, by execution of the program instructions in the processor, future prepayment behavior of said assets by said obligors, said modeling step including the sub-steps of:

i. defining at least three refinancing efficiency categories of obligors according to an expected propensity of the obligors to refinance the assets,

ii. partitioning the assets into asset pool efficiency buckets according to said refinancing efficiency categories,

iii. removing scheduled payments and core prepayments of principal which are not related to changing interest rates pro-rata from all asset pool efficiency buckets,

iv. attributing any excess of actual over scheduled prepayments to obligors refinancing assets in said asset pool, and

v. removing assets from said asset pool in a preset order according to the defined refinancing efficiency categories of obligors to reflect refinancing of assets by obligors and thus obtain a model of the remaining pool; and

e. determining, by execution of the program instructions in the processor, the current value of the asset-backed security, said current value determining step including the sub-steps of:

i. determining a core payment rate cash flow for said asset pool,

ii. generating a dual-coupled interest rate lattice from an interest rate environment information, including interest rates and respective interest rate volatilities, said lattice including a plurality of nodes representing points in time,

iii. determining, for the plurality of nodes in the lattice, whether each defined refinancing category of said asset pool would refinance based on the interest rate environment information,

iv. determining, for the plurality of nodes in the in the lattice, a respective first plurality of net cash flows for the asset-backed security, the first plurality of net cash flows including principal payments remaining in the asset pool after removal of assets prepaid due to refinancing,

v. determining, for the plurality of nodes in the in the lattice, a respective second plurality of net cash flows for the asset-backed security, the second plurality of cash flows including both principal and interest payments, and

vi. determining a value for said asset-backed security by discounting and adding the first and second plurality of net cash flows determined for the plurality of nodes in the lattice.