Back Stub
Key Back Stub in Int Rate Spec refers to optional interest rate conventions that apply on the very first time interval [T,Tₙ] over which the referenced rate accrues, in a context of a series of cash flows paid at T₁...Tₙ - such as those of a bond -, with T being the valuation date, if it is a back stub interval, i.e. if the following condition holds:
The interval [T,Tₙ] is partial, in the sense that Tₙ happens to coincide with the payment date of a rate that accrues since some time Tₙ', with Tₙ' < T
If omitted, the existing conventions apply on the back stub interval as well.