Large Category Attachments are supplemental documents included as part of the GSA Multiple Award Schedule (MAS) solicitation. These attachments provide detailed guidance, requirements, and instructions specific to each Large Category under the MAS structure — such as Information Technology, Furniture and Furnishings, Professional Services, Facilities, and others. They are an essential component of the solicitation package and play a critical role in determining the eligibility of proposed products and services.
Each Large Category Attachment outlines category-specific criteria that vendors must meet in order to be considered for award under that category. These documents serve as both technical references and compliance checklists, and are used by GSA contracting officers during the proposal evaluation process to ensure that offers align with the scope and standards of the MAS program.
Understanding and following the requirements in the Large Category Attachments is essential for any vendor submitting an MAS offer or modification. Failing to comply can lead to rejection, delays, or even ineligibility for award.
The Structure of the GSA MAS Program and the Role of Large Categories
The GSA MAS program — also known as Schedule 70 consolidated — was restructured in 2020 into a unified solicitation that encompasses Large Categories, Subcategories, and Special Item Numbers (SINs). This tiered hierarchy helps organize the vast range of commercial products and services available through the MAS, making it easier for both agencies and contractors to navigate.
Each Large Category represents a broad market sector. For example:
- Information Technology includes hardware, software, cloud services, and cybersecurity solutions
- Office Management encompasses office supplies, furniture, and document services
- Professional Services includes consulting, training, and financial advisory services
Because each category encompasses unique industries, compliance requirements, and regulatory standards, GSA developed Large Category Attachments to define and standardize what is required from vendors under each one.
What Is Included in a Large Category Attachment?
While each Large Category Attachment is tailored to its respective category, most of them share a common structure and cover similar types of information. Vendors reviewing a category-specific attachment can expect to find guidance in areas such as:
- Scope of the category and included SINs
- Eligibility criteria for products or services
- Required technical documentation or certifications
- Instructions for pricing proposals
- Templates or formats for product and service submissions
- Terms specific to the category (e.g., compliance with IT security standards)
- Restrictions or prohibitions (e.g., country of origin requirements)
For instance, the Information Technology Large Category Attachment may include instructions on submitting a Letter of Supply for hardware offerings, or detail how cloud service providers must demonstrate FedRAMP authorization. Meanwhile, the Furniture category might outline durability testing requirements or ANSI/BIFMA compliance expectations.
These documents often work in conjunction with other required attachments — such as the Solicitation Instructions, Pricing Proposal Templates, and Corporate Experience documents — to form a complete offer package.
Why Large Category Attachments Matter
Large Category Attachments are far more than administrative checklists. They are enforcement tools used by GSA to uphold the integrity of the MAS program. Contracting officers rely on these documents to:
- Verify whether a proposed offering falls within the scope of the category and SIN
- Ensure that vendors meet minimum technical and regulatory standards
- Evaluate the completeness and quality of proposal submissions
- Determine whether an item is eligible for award and publication on GSA Advantage!
For vendors, overlooking or misinterpreting the requirements in a Large Category Attachment can be costly. A submission may be deemed non-responsive or rejected altogether if key documentation is missing, pricing formats are incorrect, or product eligibility is not clearly demonstrated.
By contrast, vendors who use the attachment as a blueprint for offer development are more likely to succeed in getting awarded — and faster.
How to Use Large Category Attachments During the Offer Process
When preparing a new MAS offer or modifying an existing contract to add new SINs, vendors must consult the Large Category Attachment associated with that SIN. The attachment is downloaded from SAM.gov, along with the solicitation package.
Best practices for using these documents include:
- Reading the entire attachment before beginning proposal development
- Highlighting submission requirements, including which templates are mandatory
- Ensuring all supporting documentation (e.g., certifications, test reports, letters of supply) is complete and current
- Following instructions exactly, including file naming conventions and submission order
- Contacting the National Category Manager (listed in the attachment) if clarification is needed
GSA also provides occasional updates to Large Category Attachments, so vendors should always verify they are working from the most current version at the time of submission.
Relationship to SINs and Subcategories
While the Large Category Attachment governs the overall category, the finer granularity of eligibility is often defined at the SIN level. Within the attachment, each SIN typically has its own scope description, technical requirements, and pricing considerations.
For example, in the Professional Services category, a SIN for Training Services may have different documentation requirements than a SIN for Financial Advisory Support. The Large Category Attachment will lay out those differences clearly.
Subcategories serve as a middle layer of organization — grouping similar SINs — but they usually do not affect compliance requirements in the same direct way that SIN-specific rules do.
Updates and Revisions to Large Category Attachments
Like other solicitation documents, Large Category Attachments are subject to periodic review and revision through the Solicitation Refresh process. When GSA identifies a policy change, industry trend, or recurring issue, it may issue a refreshed version of the attachment that reflects updated expectations.
These updates are published along with the full solicitation refresh package and announced via GSA Interact. Vendors holding existing contracts may need to accept a mass modification that incorporates the revised attachment and adjust their offerings accordingly.
Because the attachments form part of the solicitation’s terms and conditions, failure to comply with new or revised requirements may jeopardize a vendor’s standing in the program.
Strategic Importance for Vendors
For contractors, understanding Large Category Attachments is not just a matter of regulatory compliance — it’s a matter of competitive advantage. Vendors who master these documents can:
- Submit more accurate and complete offers
- Reduce back-and-forth communication and administrative delays
- Avoid common rejection triggers
- Accelerate the time from offer to award
- Position themselves more credibly in the eyes of contracting officers
Moreover, because the attachments outline what is — and is not — eligible under a particular category or SIN, they help vendors align their offerings with actual federal demand, minimizing the risk of investing time in non-awardable products or services.
Conclusion
Large Category Attachments are a critical part of the GSA MAS solicitation package, serving as detailed guides for vendors seeking to offer products and services under specific Large Categories. These documents combine technical guidance with compliance enforcement, helping ensure that all offerings under the MAS are eligible, well-documented, and properly priced.
For vendors, mastering the content and intent of these attachments is an essential part of succeeding in the federal marketplace. Whether you’re a first-time offeror or an experienced Schedule holder expanding into a new category, the Large Category Attachment should be your roadmap — read carefully, follow precisely, and use it to put your best proposal forward.
