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GSA7 min readUpdated June 7, 2026

SIN 4PL: Fourth-Party Logistics (4PL) Supplies and Services Guide for GSA MAS

A Refresh 32 guide to GSA MAS SIN 4PL, Fourth-Party Logistics (4PL) Supplies and Services, including category fit, NAICS/PSC context, max order, TDR/OLM status, and offer preparation notes.

Built for
Contractors mapping offerings, pricing support, catalog files, labor categories, or Add SIN modifications to official GSA MAS scope
By the end
Understand where SIN 4PL fits and what evidence to prepare before using it in an offer or modification.
Field guide

When SIN 4PL fits

Scope fit
A close-looking SIN can still be wrong if the subcategory, PSC, NAICS, or deliverable story points elsewhere.
Signal
This SIN encompasses all commercially available Fourth-Party Logistics (4PL) delivery models required for a full solution that includes, at a minimum, providing the product, logistical support, transportation, inventory management, and all other services necessary to support 4PL operations.^^^^Specific services include, but are not limited to: Vendor-Owned/Vendor-Managed Inventory (VMI) Services, such as resupply of designated items by the Vendor through regularly scheduled reviews of on-site inventory counts, removal of damaged or outdated goods, and the re-stocking of inventory to predetermined levels at their specified locations and customer support.^^^^4PL services can be delivered in various 4PL models, separately or in combination: Brick and Mortar Retail Storefronts; Tool Rooms and Issue Points; Virtual ServMarts; Satellite Locations; In-Store Referral Ordering; Direct Delivery; and Online Catalogs.^^^^General Requirements ^^Items must: ^^(1) Represent a full and broad catalog (as outlined in SCP-FSS-001); and ^^(2) Be within scope of at least one existing MAS SIN; and ^^(3) Comply with all requirements outlined in corresponding SIN(s) ^^^^NOTE: Items proposed under this SIN do not have to be awarded under another SIN in the MAS program, but must be commercial in nature and meet all category-specific requirements outlined in the corresponding category attachment. ^^NOTE: Offerors shall provide fully burdened rates of products offered under the consolidated schedule. Proposed price lists must specifically cover fully-burdened rates which include the product and the 4PL Services. Proposed prices are firm fixed price (FFP) and must represent fully-burdened rates inclusive of product, service and freight cost. ^^^^Delivery Requirements: F.O.B. Destination, in accordance with the clause at FAR 52.247-34 F.O.B. DESTINATION (see most current Solicitation for clause effective date), is required for all domestic deliveries. For the purposes of the 4PL SIN, "domestic delivery" is delivery within the 48 contiguous states, Alaska, Hawaii, Puerto Rico, Washington, DC, and U.S. territories. Domestic delivery also includes a port or consolidation point, within the aforementioned areas, for orders received from overseas activities.^^^^Note: U.S. territories include 48 contiguous states, Washington, DC, Alaska, Hawaii, Puerto Rico and Guam.
Response
Compare the buyer's requirement to the official SIN language before forcing the opportunity into a familiar lane.
Service proof
Product SINs can create TAA, letter-of-supply, CSA, EULA, or FCP Product File questions.
Signal
The SIN supports service work, labor categories, deliverables, and pricing support.
Response
Prepare labor category descriptions, service narratives, past performance, FCP Services Plus data, and pricing support.
Modification path
Adding a SIN can affect catalog files, service descriptions, pricing support, and buyer-facing records.
Signal
The contractor wants to add this SIN after award or adjust offerings tied to it.
Response
Use the Add SIN and Add Product/Labor Category modification pages to plan scope, price, and evidence changes.
Refresh 32

SIN 4PL quick facts

A compact view of the official SIN record from the user's Refresh 32 MAS offerings workbook.

Category
Miscellaneous
Complementary SINs
NAICS
322230, 332321, 332510, 332999, 339940
NAICS codes associated with the SIN in the workbook.
PSC
5340
Product Service Code mapped to the SIN.
Max order
$750,000
Ordering threshold for seeking additional price reductions.
Part 1

What SIN 4PL covers

This SIN encompasses all commercially available Fourth-Party Logistics (4PL) delivery models required for a full solution that includes, at a minimum, providing the product, logistical support, transportation, inventory management, and all other services necessary to support 4PL operations.^^^^Specific services include, but are not limited to: Vendor-Owned/Vendor-Managed Inventory (VMI) Services, such as resupply of designated items by the Vendor through regularly scheduled reviews of on-site inventory counts, removal of damaged or outdated goods, and the re-stocking of inventory to predetermined levels at their specified locations and customer support.^^^^4PL services can be delivered in various 4PL models, separately or in combination: Brick and Mortar Retail Storefronts; Tool Rooms and Issue Points; Virtual ServMarts; Satellite Locations; In-Store Referral Ordering; Direct Delivery; and Online Catalogs.^^^^General Requirements ^^Items must: ^^(1) Represent a full and broad catalog (as outlined in SCP-FSS-001); and ^^(2) Be within scope of at least one existing MAS SIN; and ^^(3) Comply with all requirements outlined in corresponding SIN(s) ^^^^NOTE: Items proposed under this SIN do not have to be awarded under another SIN in the MAS program, but must be commercial in nature and meet all category-specific requirements outlined in the corresponding category attachment. ^^NOTE: Offerors shall provide fully burdened rates of products offered under the consolidated schedule. Proposed price lists must specifically cover fully-burdened rates which include the product and the 4PL Services. Proposed prices are firm fixed price (FFP) and must represent fully-burdened rates inclusive of product, service and freight cost. ^^^^Delivery Requirements: F.O.B. Destination, in accordance with the clause at FAR 52.247-34 F.O.B. DESTINATION (see most current Solicitation for clause effective date), is required for all domestic deliveries. For the purposes of the 4PL SIN, "domestic delivery" is delivery within the 48 contiguous states, Alaska, Hawaii, Puerto Rico, Washington, DC, and U.S. territories. Domestic delivery also includes a port or consolidation point, within the aforementioned areas, for orders received from overseas activities.^^^^Note: U.S. territories include 48 contiguous states, Washington, DC, Alaska, Hawaii, Puerto Rico and Guam.

The official record maps this SIN to NAICS 322230, 332321, 332510, 332999, 339940 and PSC 5340. Those codes are not the whole strategy, but they help explain how the offering is categorized for buyers and reviewers.

Part 2

How to prepare the offer story

For service-oriented SINs, keep the service description, labor categories, pricing support, and past-performance examples aligned. A reviewer should be able to see what work is being sold, who performs it, and why the rate story is defensible.

If the SIN is being added through eMod, write down what changes operationally: new scope, new pricing, new files, catalog impact, and who owns maintenance after approval.

Part 3

Buyer and SEO language to keep straight

Use the SIN number, title, category, and subcategory together: SIN 4PL - Fourth-Party Logistics (4PL) Supplies and Services - Miscellaneous - Complementary SINs. That combination helps a buyer understand the lane quickly and helps the page avoid becoming a vague keyword page.

When writing capability language, explain the actual deliverables and evidence. Do not make the SIN carry the whole message by itself.

Examples

What this looks like in practice

Real-world checkHow to test SIN 4PL before building files

Start with the official title and description: Fourth-Party Logistics (4PL) Supplies and Services sits under Miscellaneous > Complementary SINs. Then compare your actual commercial offering to that scope, not only to the NAICS code.

If the fit still looks strong, build the proof stack: offering description, pricing support, past performance or product support, and any SIN-specific files the current GSA instructions require.

  • Confirm scope language.
  • Check NAICS and PSC signals.
  • Match the pricing file to the offering type.
  • Keep the support package reviewer-friendly.

Frequently asked questions

Is SIN 4PL part of TDR?

The Refresh 32 workbook marks TDR as Y for this SIN. GSA states that TDR became mandatory across MAS SINs with Refresh 31, so contractors should still verify current contract reporting instructions in official GSA sources.

Can order-level materials be used with SIN 4PL?

The workbook marks OLM as Y. OLM treatment should always be verified against the current MAS solicitation, mass modifications, and contract-specific instructions.

Should I pick a SIN only because the NAICS matches?

No. NAICS helps, but SIN selection should be based on the actual offering, official SIN description, category/subcategory, pricing files, and buyer acquisition path.