If your firm wants to obtain a GSA contract but does not manufacture the products it sells, then a letter of supply is needed. GSA sometimes also refers to this as a Letter of Supply (LOS), or occasionally a Letter of Commitment. This requirement is noted in Clause I-FSS-644 – Dealers and Suppliers of the Solicitation.
A GSA Letter of Supply serves this purpose:
If you are is a dealer or reseller of a product, you must ask your supplier/manufacturer for a Letter of Supply for each brand offered.
This letter must be
The solicitation contains a Letter of Supply template.
This image is an example of a GSA Letter of Supply / Letter of Commitment
Click here to see the Letter of Supply text.
This is a common question, and quite often, if you asked a GSA contracting officer, they would answer yes. Less experienced CO's would almost certainly respond yes.
Also, GSA solicitations tend to suggest that a GSA LOS is mandatory. Take for example GSA IT Schedule 70. In the solicitation's general proposal instructions, it states that GSA may reject offers that do not include a letter of supply if the firm is not the manufacturer.
Later it states that a LOS is not required for used or refurbished equipment under SIN 133-9, which to many, implies it is necessary in all other cases.
But GSA's actual policy is quite the opposite. A Contracting Officer is required only to determine if your firm has a sufficient source of supply. GSA's policy is that a LOS is not needed so long as other evidence is submitted that substantiates the vendor has an acceptable source of supply.
At the 2012 GSA Expo, Mark Lee, Policy Chief, Office of Acquisition Management in the GSA Federal Acquisition made this point quite clear, as shown in the following brief video clip. The Office of Acquisition Management is responsible for establishing the standards and framework for managing the acquisition workforce under policy established by the GSA Chief Acquisition Officer. The Office of Acquisition Management leads, supports and facilitates the review of Federal Acquisition Service programs and procedures.
Go to the 3 minute mark for the LOS Q&A: