Taiwan is set to significantly expand its arsenal of mobile rocket systems amid growing tensions in the Taiwan Strait, with plans to acquire a total of 111 High Mobility Artillery Rocket Systems (HIMARS) from the United States by the end of this year. This build-up comes in contrast to mainland China’s deployment of more than 200 of its PHL-16 (also known as PCL-191) systems, highlighting a potential future exchange of missile fire should conflict arise.

However, the question of ammunition availability remains a critical concern. Two key long-range missiles compatible with HIMARS—the Army Tactical Missile System (ATACMS) and the Precision Strike Missile (PrSM)—have seen their global stockpiles heavily depleted, primarily due to extensive use in recent conflicts, including the ongoing war involving the United States and Iran. The U.S. Army reportedly has expended nearly all of its worldwide reserves of these missiles, raising uncertainty over Taiwan’s ability to replenish its stocks despite an approved order of 504 ATACMS, which includes 64 already delivered and 20 more expected this year.

Production challenges compound the issue, as Lockheed Martin, the manufacturer of ATACMS, is in the process of phasing out the system. The pace at which new missiles can be produced and supplied remains unclear, raising strategic questions about sustained missile availability in a potential Taiwan Strait confrontation.

China, meanwhile, continues to expand its missile inventory. The Pentagon estimated that as of 2024, China possessed at least 3,150 ballistic missiles and 300 ground-launched cruise missiles—a significant increase since 2015. A recent analysis identified 81 Chinese companies involved in the missile supply chain, nearly triple the number documented in 2013, with many reporting record sales in 2025. This buildup appears to coincide with the depletion of U.S. missile stockpiles.

U.S. munitions shortages have been publicly acknowledged in a Pentagon inspector general report released in October, which detailed expenditures during Operation Epic Fury—a joint U.S.-Israeli military campaign targeting Iran. Of the $33.4 billion spent between February and June 2023, approximately 67% was allocated to munitions. The report highlighted resulting “strategic inventory shortfalls” and noted industrial base limitations hindering rapid resupply.

The depletion extends beyond missiles. By August 2023, nearly 80% of the U.S. Terminal High Altitude Area Defense (THAAD) missile inventory and about half of Patriot interceptor missiles had been expended compared to pre-conflict levels, with significant quantities of Tomahawk cruise missiles and other interceptors also used.

Efforts to restore stocks face enduring challenges. Production increases for conventional munitions have been slow, partly due to a diminished industrial base resulting from decades of consolidation within the U.S. defense industry. Since the 1990s, the number of major U.S. defense contractors has fallen from more than 50 to just five dominant firms, which has contributed to limited competition and higher unit costs. This has constrained procurement volumes even as defense budgets rise.

By contrast, China’s defense industry remains heavily state-controlled, enabling more direct alignment with military requirements and strategic objectives. Analysts note that China pursues full domestic sourcing and indigenization across its supply chain, which enhances control over production capacity, costs, and delivery schedules. This approach has allowed China to expand its missile capabilities rapidly while containing expenses.

The widening gap in production and inventory readiness between the U.S. and China underscores a key strategic consideration in any potential Taiwan Strait conflict. While Taiwan’s acquisition of HIMARS systems presents a significant boost to its defense capacity, concerns over missile availability and replenishment timelines could affect operational sustainability. Meanwhile, China’s growing missile arsenal continues to reflect sustained investment and prioritization amid an evolving regional security landscape.