What is a complementary SIN?

Complementary Special Item Numbers (SIN) are awarded with other Multiple Award Schedule (MAS) SINs to allow for a total solution, including miscellaneous order level items. There are six types of complementary SINs available through the contract and each has a different function.


Ancillary refers to supplies or services that do not fall under any other SIN’s scope. These supplies or services are purchased with supplies or services offered on schedule. They are an integral part of the offerings and allow the company to offer a total package of their services or products. The pricing for these items or services is determined when the schedule or modification is negotiated.


ANCRA refers to ancillary repair or alteration services ordered in accordance with services or products currently on schedule. The tasks associated with this SIN are simple in nature. Examples include delivery and installation such as painting, basic electrical or plumbing or landscaping. ANCRA is commonly found in support of SINs under the subcategories; Facilities Supplies, Facilities Solutions, Facilities Services, Structures, Facilities Maintenance and Repair, Furniture Services, Flooring, Machinery and Components, Fuel Management, Industrial Products, Industrial Products and Services Maintenance and Repair, Office Services, Logistical Services and Laboratory Equipment. The pricing for these items or services is determined when the schedule or modification is negotiated.


NEW can be used in reference to products, technology, and services that are provided commercially, but do not follow under one of the existing SINs on schedule.


Order-Level Materials (OLM) are supplies or products obtained in support of a specific task order or delivery order placed against the contract. Pricing for these items is not established during the negotiation of the contract but at the task order or Blanket Purchase Agreement level.

OLM have the following restrictions:

  • Must not be primary basis of order
  • Must be less than 33 percent of overall value of the order or BPA
  • Only authorized under Time & Material (T&M) or Labor Hour Contract Line Item (CLIN)
  • If Order-level Materials are above the Simplified Acquisition Threshold (SAT), vendors must submit three quotes (vendor concern) for the ordering activity contracting officer
  • Contracting officer must determine all prices are fair and reasonable (contracting officer concern)

238910 Installation and Site Preparation Services

238910 refers to the installation and services required for site preparation. These services must be purchased with products offered under certain SIN categories and subcategories. Products offered under the Facilities Subcategory “Structures”, Security and Protection Subcategory “Security Systems” and Industrial Products and Services subcategory “Industrial Products” qualify to use this complementary SIN.


Fourth-Party Logistics (4PL) covers all available 4PL delivery models required for providing product support, transportation, inventory management, and other services to support these operations. This SIN is divided into two categories Vendor-Owned/Vendor-Managed Inventory Services or Vendor-Owned/Vendor-Consigned Inventory Services. These two categories can be delivered in various ways such as Brick and Mortar Storefronts, Online Catalogs, Direct Delivery, and Satellite locations.

Should I have a complementary SIN on my GSA schedule?

Having a complementary SIN on your MAS Schedule allows you to offer government agencies a total package. Agencies can easily come to your schedule for a product or service and all the other miscellaneous parts of the offering. The SINs are also often needed on schedule to win a Blanket Purchase Agreement.

How can I add complementary SINs to my schedule?

Each of these complementary SINs have different requirements that are listed in the solicitation and requested from your Contracting Officer. Coley has helped clients successfully add these complementary SINs to their schedules and is available to help answer questions, complete the necessary forms, and communicate with contracting officers.

Coley has over 20 years’ experience helping thousands of companies obtain their GSA Schedule. We are available to help make the process of adding these complementary SINs easy. Contact us today at hello@coleygcs.com,  210-402-6766 or schedule a call to begin obtaining the support you need to keep your GSA contract competitive and in compliance —a critical step in your journey to success in the government market.

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