Input service distributor, explained

An Input Service Distributor or ISD is a mechanism used by businesses with multiple registrations when common input services are billed centrally but the credit belongs across locations.

Typical example

Head office pays for software, audit, marketing or insurance used by several branches. Instead of leaving all the credit in one place, the ISD mechanism distributes it to the relevant registrations.

Why this exists

Without a proper mechanism, businesses either lose credit or claim it in the wrong registration, both of which become audit issues.

Who should care

Single-location firms can ignore this. Multi-state or multi-registration businesses should understand it early.