U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


  1. Home
  2. Pre-Positioned War Reserve Materiel (PWRM)

Pre-Positioned War Reserve Materiel (PWRM)

ALCL 188


Alternate Definition

Prepositioned War Reserve Materiel (PWRM) – War reserve materiel and equipment strategically located to facilitate a timely response in support of combatant commander requirements during the initial phases of an operation. PWRM includes starter stock and swing stock intended to be used until sustainable logistical lines of communication have been established. (DoDD 3110.07)

Prepositioned War Reserve Materiel (PWRM) – War reserve materiel strategically located to facilitate a timely response in support of combatant commander requirements during the initial phases of an operation. (CJCSI 4310.01F)

Alternate Definition Source

DoD Directive 3110.07 and CJSSI 4310.01F

General Information

Prepositioning Provides Flexibility for Initial Phases of an Operation

Prepositioned War Reserve Materiel (PWRM) provides initial equipment, repair parts, supplies, and munitions to support weapon systems and military forces during contingency operations until replenishment processes (lines of communications) can be established to meet demand. 

In accordance with CJCS Instruction 4310.01F, Logistics Planning Guidance for Pre-Positioned War Reserve Materiel, “PWRM provides the greatest practical flexibility to respond to a spectrum of regional contingencies while reducing the demand on the global transportation network.” The instruction directs the Military Services to size, manage, and pre-position resources in Combatant Command (e.g., U.S. Indo-Pacific Command) areas of responsibility. Pre-positioned war reserve capabilities (PWRC), including ashore and afloat unit type sets, place equipment and supplies at or near the point of planned use to reduce reaction time and ensure timely support. These include subsistence items, shelters, etc. including, for example Basic Expeditionary Airfield Resources (BEAR) for Air Force units.  Pre-positioned war reserve stocks (PWRS), including those ashore managed by the Services and on pre-positioning ships managed by Military Sealift Command, provide initial stockpiles of materiel. Starter stock is generally assigned to and located in or near a theater of operations. Swing stock, ashore or afloat, is not designated to any single Combatant Command (CCMD) but can augment WRM requirements of a CCMD.

Benefits of PWRM include:

  • Maximizes warfighter support
  • Achieves the greatest agility and flexibility
  • Reduces reaction time
  • Support forces worldwide in the initial phases of operations
  • Minimizes DoD expenses

DoD Directive 3110.07, Pre-Positioned War Reserve Materiel (PWRM) Strategic Policy establishes policy and assigns responsibilities for managing PWRM. Its implementing instruction, DoD Instruction 3110.06, War Reserve Materiel (WRM), directs the Military Departments to “size, acquire, manage, and position WRM to achieve the greatest practical flexibility and responsiveness to a full spectrum of regional contingencies, while minimizing DoD investment in WRM to reduce reaction time and to sustain forces.” In addition to prepositioned WRM, the instruction directs DoD Component Heads to “identify alternative materiel sourcing strategies, e.g., host nation support, cross-servicing, acquisition, or partnering agreements” and directs the Defense Logistics Agency (DLA) to coordinate with the Military Departments to “contract, stock, or perform storage and distribution functions for bulk petroleum” and other WRM.


DoD Product Support Manager Responsibilities for PWRM

DoD Product Support Managers (PSMs), charged with managing the package of support functions required to field and maintain the readiness and operational capability of weapon systems, must factor PWRM into their Product Support Strategies A PSM’s duties include managing entire fleets of aircraft, combat vehicles, ship classes, and equipment, and the Joint Capabilities Integration and Development System (JCIDS) Manual states the Materiel Availability Key Performance Parameter (Am KPP) includes prepositioned assets in the total system population to be managed. This applies to both systems and equipment (such as support equipment). 

DoD Instruction 5000.91, Product Support Management for the Adaptive Acquisition Framework, directs Program Managers (PM), through their PSMs, to “evaluate and select materiel management solutions that balance support goals, total supply chain costs, and performance factors.” For weapon systems, particularly Class IX repair parts, materiel management solutions include PWRM, which is procured and managed in collaboration with the Warfighter (e.g., lead command) and product support integrators and product support providers. If WRM requirements are known early in the life cycle, PSMs may wish to consider Spares Acquisition Integrated With Production, where appropriate and allowed by DoD policy. 

During Operations and Sustainment, supply chain management providers and life cycle management activities for munitions, common support equipment, etc. generally provide PWRM for weapon systems, as well as readiness spares packages (RSPs) (formerly known as war readiness spares kits (WRSK)) with which units deploy to complement PWRM. Finally, if contractor logistics support is part of the product support strategy, the PSM or Product Support Integrator (PSI) may place PWRM requirements on contract, as applicable for repair and replenishment actions.


For Further Reading

The Congressional Research Service published a 2-page primer highlighting the purpose of PWRM, applicable statutes, and a description of Army, Navy and Marine Corps, and Air Force PWRM programs.

Service Policy

In an article describing strategies for prevailing through Contested Logistics, the Assistant Secretary of Defense for Sustainment, HON Christopher J. Lowman, stated “A significant portion of combat power will require resupplying underway to distributed combat operations or prepositioning of war reserve materiel globally to provide an initial capability.” Explore the article for related strategies for supporting weapon systems.

The Government Accountability Office (GAO) published a report, Prepositioned Stocks: DoD Needs Joint Oversight of the Military Services’ Programs (GAO-19-244), which made six recommendations for the Secretary of Defense.