In this article, learn about:
- What separates OEM parts from aftermarket parts when you are the one making them
- How Caterpillar treats its production supply base and its aftermarket supply base differently
- Where EDI, advance ship notice, and item setup requirements diverge between the two channels
- How to weigh which channel fits your business, and what industrial supply connectivity each one asks of you
Most suppliers find Caterpillar the same way. It starts with registering a company profile in the Supplier Registration Portal. The profile then goes to procurement and supply chain professionals who review it as needs come up. And once there is a match, someone from Caterpillar reaches out. Caterpillar is direct that submitting a profile does not guarantee a business opportunity.
What registration does not tell you is which Caterpillar you are about to sell into. A company that size does not run one supply chain. It runs a production supply base feeding new machine assembly, and a separate aftermarket and remanufacturing operation feeding parts and service. Those carry different qualification paths, different documentation expectations, and different connectivity work. Suppliers who treat the Original Equipment Manufacturers (OEM) and aftermarket question as a definition to memorize usually find out otherwise at the first rejected shipment notice.
What Are OEM Caterpillar Parts and Aftermarket Caterpillar Parts?
An OEM part is made by or for the equipment manufacturer and carries its specification. An aftermarket part is made by a third party to fit the same machine. That is the whole definition, and search engines already are already helpful for an equipment owner deciding what to install at a repair shop.
That framing is no help to the company making the part. If you manufacture components, OEM versus aftermarket is less a purchase decision you make than a description of which part of your customer's organization buys from you, under which agreement, and with which paperwork.
Why Does the Aftermarket Carry So Much Weight in Heavy Equipment?
Parts and service are where the profit concentrates, more than the revenue. Deloitte reports that many manufacturers generate 40 to 50 percent of overall profits from services, and expects aftermarket parts and services to keep delivering more than half of manufacturer profit. BCG puts gross margins on spare parts and consumables at around 50 percent of sales, well above what the original machine earns.
Both figures describe industrial manufacturing broadly rather than heavy equipment specifically, so treat them as directional. The pattern holds regardless: an OEM with that much profit riding on parts and service will build real structure around it, and that structure is what a supplier runs into.
Caterpillar structures around that. Cat Reman runs remanufacturing on a core return basis: A customer returns an end-of-life component through a dealer for core credit, the core is inspected at a core processing facility, and it is rebuilt to match the performance specifications of new Cat products. That is a supply chain with its own inputs, its own inspection gates, and its own supplier base, rather than just a footnote to the production line.
How Does Caterpillar Separate Its OEM and Aftermarket Supply Base?
Caterpillar draws the line publicly. At the fourth annual Supplier Excellence Recognition event in September 2025, roughly 800 suppliers were recognized in three categories: Supplier Excellence, Aftermarket Excellence, and Supplier of the Year. Aftermarket Excellence is its own award track, with winners named by division, including the Product Support and Logistics Division and Cat Reman.
A recognition program is a visible signal, not proof that two fully separate qualification systems exist behind it. The awards could reflect a real difference in how the two supply bases are sourced and managed, or they could reflect reporting structure. Suppliers should ask rather than assume.
What Is Supplier Connect and Where Does It Fit?
Supplier Connect is the portal Caterpillar uses for both potential and existing suppliers. For companies not yet doing business with Caterpillar, it publishes the high-level requirements. For active suppliers, it is the entry point into the Caterpillar systems and processes suppliers are expected to follow, and it is where Caterpillar hosts its electronic data interchange (EDI) documentation.
That is where the OEM and aftermarket question stops being academic. Access to the portal is common ground. What the portal asks of you afterward depends on which relationship you are in.
What Breaks When Suppliers Treat the Two Channels as Interchangeable?
The failure mode is rarely dramatic, and nothing announces itself. A supplier maps its transactions once, assumes the mapping covers everything under one customer name, and then hits friction on a specific document or a specific item.
Advance Ship Notices
An advance ship notice (ASN) tells the receiving side what is coming, in what packaging, against which order, before it arrives. Receiving requirements are not uniform across an organization the size of Caterpillar. A production plant receiving line side material and a parts distribution center receiving replenishment stock are solving different problems, and the notice each expects can reflect that.
Item Data Setup
Item setup poses another risk. Part numbering, unit of measure, packaging hierarchy, and the identifiers a buyer indexes on can differ between a production program and an aftermarket program. When they do, the mismatch does not surface at setup. It surfaces at receipt as a rejection, and then someone spends a week reconciling it.
What Caterpillar Parts Suppliers Should Check First
Before assuming one integration covers both channels, double-check which division owns the relationship, which documents that division requires, and whether item identifiers carry over. Ask during qualification, not after the first purchase order.
Which Channel Should Your Business Pursue?
There is no default answer, and plenty of suppliers run both. What separates the two decisions:
- Volume shape. Production programs tend toward scheduled, forecastable volume tied to build rates. Aftermarket demand follows failure and service patterns, which are steadier over a year but less predictable week to week.
- Qualification depth. Feeding a production line generally means engineering approval, tighter change control, and a longer runway before first revenue.
- Connectivity burden. Both channels require reliable data exchange. They do not necessarily require the same documents, the same frequency, or the same item structure.
- Remanufacturing fit. If your part has a viable core, the Cat Reman side is a distinct opportunity with its own return and inspection logistics.
Choosing a channel is closer to choosing an operating model than choosing a customer.
Frequently Asked Questions
Is Supplier Connect the same as the Supplier Registration Portal?
They are related but not identical. Caterpillar directs prospective suppliers to submit a company profile through a registration form, while Supplier Connect is the broader portal covering requirements for potential suppliers and system access for existing ones.
Can one supplier sell into both the OEM and aftermarket channels?
Yes, and many do. The point is that doing so may mean maintaining more than one set of requirements under a single customer relationship, rather than one integration that covers everything.
Does aftermarket business have lower standards than OEM production?
No, and different is not the same as lower. Aftermarket and remanufacturing programs carry their own qualification, quality, and documentation requirements, and Caterpillar recognizes aftermarket supplier performance in a dedicated award category.
How long does Caterpillar keep a supplier profile on file?
Caterpillar archives profiles after 12 months without an invitation to do business and recommends updating the profile if no business has been awarded in that window.
Ready To Make the Connectivity Question the Easy Part?
Whichever channel you qualify for, the underlying requirement is the same: accurate, reliable data exchange with a demanding trading partner, in whatever form that partner asks for it. SPS Commerce works with manufacturers and industrial suppliers on exactly that layer, so the connectivity work is not what slows down a new program.
Not ready to talk about integration? The Supply Chain Source has articles and guides for suppliers working through requirements like these.