lying underneath / basic or fundamental / implicit

(finance) The entity from whose performance a derivative derives its value.

present participle of underlie

plural of underlying

(rare, obsolete) At a lower level. / (chiefly colloquial) In an inferior or inadequate manner; insufficiently (chiefly in opposition to overly).

(dialectal) Poor; inferior.

Misconstruction of underlay / Misconstruction of underlain

Nonstandard spelling of underlie.

That which underlies.

plural of underlier