GWACs, IDIQs, and GSA Multiple Award Schedules are all types of Indefinite Delivery, Indefinite Quantity (IDIQ) contracts, but they differ in their scope, administering agency, and how they are accessed. An IDIQ is a contract type that provides for an indefinite quantity of supplies or services during a fixed period, with orders placed against it. The Federal Acquisition Regulation (FAR) Part 16.5 governs IDIQs.
A GSA Multiple Award Schedule (MAS) contract is a specific type of IDIQ that GSA administers, covering a wide range of commercial products and services. My firm has done some work through BPAs on a GSA Schedule. It is continuously open for new offers. A Governmentwide Acquisition Contract (GWAC) is also an IDIQ, but it is typically focused on information technology and is awarded by one agency for use by all federal agencies. For example, NASA SEWP is a well-known GWAC. Both GSA Schedules and GWACs are popular contract vehicles for federal agencies to procure goods and services efficiently.
As a WOSB, pursuing these vehicles as a prime contractor or a subcontractor can offer different advantages. Getting on a GSA Schedule or a GWAC can be a significant effort, but it opens up many opportunities for direct awards or task orders. Subcontracting is often an easier entry point, allowing you to gain experience and build relationships with larger primes who already hold these contracts.