Marathon Petroleum Procurement and Buying Center: Who Controls Vendor Selection

Marathon Petroleum is the largest refiner in the United States, and its procurement organization reflects that scale. Vendor selection at Marathon operates through a dual structure: corporate procurement in Findlay, Ohio sets the qualification standards and commercial frameworks, while site level teams at each refinery control which qualified vendors actually receive work. Understanding both layers, and the Senior Role contacts who hold decision authority at each, is essential for any vendor pursuing Marathon business.

This guide maps the Marathon buying center, explains the corporate vs site split, and identifies the decision functions that control vendor selection at Gulf Coast facilities. For a broader account strategy perspective, see our complete guide to selling to Marathon Petroleum.

The ISNetworld gate

Before any buying center discussion, vendors need to understand that Marathon operates a hard gate on ISNetworld compliance. Every contractor performing work at a Marathon facility must hold an ISNetworld grade of A or B. This is not a preference or a weighted evaluation factor. It is a binary qualification requirement. A vendor with a C grade will not receive bid packages, will not be considered for turnaround scopes, and will not be able to execute work on site regardless of pricing or technical qualifications.

Marathon's ISNetworld configuration includes operator specific questionnaires that go beyond standard ISNetworld requirements. These questionnaires cover Marathon specific safety protocols, training standards, and operational requirements. Vendors who are ISNetworld compliant for other operators should not assume they are automatically compliant for Marathon. Review and complete the Marathon specific modules before pursuing any opportunity.

Corporate vs site level: where decisions live

Marathon's procurement structure creates two distinct decision environments. Corporate procurement in Findlay manages the approved supplier list, sets commercial terms for system wide contracts, negotiates frame agreements for major equipment categories, and tracks contractor performance across all 16 refineries. The corporate supply chain team holds authority over which vendors are eligible to work anywhere in the Marathon system.

Site level procurement at each refinery manages the day to day purchasing and, critically, controls the turnaround contractor selection process. The turnaround manager at Galveston Bay has the authority to build a preferred contractor list for turnaround events at that facility, as long as the contractors meet the corporate qualification requirements. The site procurement team processes purchase orders, manages local vendor relationships, and handles MRO purchasing within established frameworks.

Senior Role decision functions

At each Marathon Gulf Coast facility, five Senior Role functions collectively control the vendor selection process. Each function has different authority, different priorities, and different relationship dynamics.

The turnaround manager builds the preferred contractor list for each turnaround event. This is the single most important contact for service vendors targeting turnaround work. The turnaround manager evaluates contractors based on safety performance, prior Marathon execution history, crew availability, and site familiarity. They report to the turnaround director, who provides strategic oversight and approves the final contractor list for major events.

The maintenance manager controls routine service vendor preferences and MRO purchasing priorities. For vendors selling ongoing maintenance services, inspection programs, or equipment service agreements, the maintenance manager is the primary decision contact. The maintenance manager also influences turnaround vendor selection by providing input on which contractors have performed well on routine maintenance work.

The reliability engineer and reliability manager control the specification for equipment replacements, inspection programs, and predictive maintenance technologies. Vendors selling inspection technology, condition monitoring systems, or reliability consulting services need relationships at this level. The reliability function at Marathon is data driven, and vendors who can demonstrate measurable reliability improvements have a stronger value proposition than those selling on relationship alone.

The operations manager at each facility has veto authority over vendor selection for any scope that impacts unit operations. While the operations manager does not typically initiate vendor selection, their approval is required for turnaround scopes that involve critical path work on operating units. Operations managers prioritize safety, schedule adherence, and minimal disruption to production.

The site procurement manager handles commercial terms, purchase order processing, and vendor compliance monitoring. While procurement does not typically select vendors, the procurement manager controls the administrative qualification process and can accelerate or delay a vendor's path to site access.

How vendor decisions get made at Marathon

The formal Marathon procurement process involves a structured bid evaluation with safety, technical, and commercial scoring. Bid packages for turnaround scopes include detailed scope descriptions, safety requirements, commercial terms, and evaluation criteria. The turnaround manager leads the technical evaluation, procurement leads the commercial evaluation, and the turnaround director reviews and approves the final selection.

The informal process matters equally. Marathon's buying center forms preferences before the formal process begins, based on prior performance, industry reputation, and relationship trust. Vendors who have successfully executed work at Marathon previously have a built in advantage because the turnaround manager and maintenance manager already have direct experience with their crew quality, safety culture, and execution capability.

New vendors entering the Marathon system for the first time face a higher qualification bar. The most effective strategy is to pursue a small initial scope, a minor unit outage or a subcontract role on a larger event, to establish a performance record within the Marathon system. Once you have a Marathon track record, the buying center's confidence in your capability increases significantly, and you become eligible for progressively larger scopes.

ExecGraph maps the complete buying center at Marathon Galveston Bay and Garyville, including the turnaround manager, maintenance manager, reliability team, operations manager, and procurement contacts. The platform tracks role changes so vendors can identify when new leadership creates entry opportunities at either facility. For turnaround specific timing, see the Galveston Bay turnaround schedule for 2026.