By Eric Gomez
The backlog of US arms sales announced but not delivered to Taiwan did not change in March 2025. As shown in Figure 1, the backlog remains $21.54 billion.
This lack of movement in the backlog’s topline number should not be confused with a lack of activity in March. New data from the Stockholm International Peace Research Institute (SIPRI) indicates partial delivery of a major arms sale occurred in 2024. Additionally, after a roughly two-year delay, Taiwan’s first F-16 Block 70/72 fighter aircraft rolled off the assembly line.
Sources: Defense Security Cooperation Agency: Press Release, US Congressional Record; “Major Arms Sales,”; DCSA Release; DCSA Major Arms Sales; DCSA Press Media TECRO; SIPRI Arms Transfers Database, Stockholm International Peace Research Institute; US Congressional Record; “Major Arms Sales,” Defense Security Cooperation Agency; “Defense News,” Ministry of National Defense, Republic of China; “Letter from the Ministry of National Defense, Submitting a Written Report on the ‘Implementation Status of US Arms Sales to Taiwan’ for the 2024 Budget Resolution,” Ministry of National Defense, June 12, 2024; and “Excerpt from ‘Ministry of National Defense 2024 Annual Budget Assessment Report’,” Ministry of National Defense, October 2023; and “Information on US Arms Sales to Taiwan,” Ministry of National Defense, October 30, 2024.SIPRI’s 2025 Arms Transfers Database
New SIPRI Dataset Reveals a Large Delivery in Progress
SIPRI released its annual update to the Arms Transfer Database in March 2025, which brings the data current as of the end of 2024. Tracking the delivery status of arms sales, to Taiwan or any other country, is a very difficult task. SIPRI’s dataset has been a valuable source of information for the Taiwan arms backlog project since its first publication in November 2023.
However, SIPRI’s data is also imperfect. The 2025 edition of the dataset, for instance, categorizes the sale of 11 HIMARS systems to Taiwan as partially delivered, despite the Ministry of National Defense (MND) confirming full delivery in late 2024. SIPRI is also missing two major Taiwan arms sales from its dataset: a plus-up of 18 additional HIMARS and 100 PAC-3 MSE interceptors for the Patriot air and missile defense system. In SIPRI’s defense, confirming the existence of these two arms sales was not easy. Because both cases were modifications to older arms sales, their notifications were published in the Congressional Record instead of the Defense Security Cooperation Agency’s website, which is a much more readily accessible source of information.
For the most part, SIPRI’s 2025 update comports with other information I collected in 2024 about the arms sale backlog, but there was one noteworthy development.
According to SIPRI’s dataset, Taiwan has started receiving components of the Harpoon Coastal Defense System or HCDS, a truck-mounted version of the Harpoon anti-ship missile. In October 2020, Congress received notification of a $2.37 billion sale of 100 HCDS launchers, 400 missiles, and 25 radar trucks. The HCDS case is the second-largest arms sale by dollar value in the backlog. In September 2024, Taiwan’s Liberty Times reported that some HCDS equipment had arrived in Taiwan, but I did not feel confident coding HCDS as partially delivered at that time because the Liberty Times reporting was not well detailed.
Based on SIPRI’s data, I feel confident in changing the HCDS sale to partially delivered. Like the Abrams tank sale, this partial delivery status is expressed by a different color in the Figure 1 pie chart. As a reminder, the dollar value of the Taiwan arms sale backlog will not be reduced until final delivery of the arms sale occurs because trying to estimate a dollar value for partial delivery would be too difficult and likely inaccurate. Partial delivery of arms sales worth more than $1 billion are displayed visually in Figure 1 and noted with yellow text in Table 1.
First New F-16 Rolls Off Delivery Line
The largest arms sale in the backlog, 66 F-16 Block 70/72s valued at $8 billion, also saw a major development in March 2025, as the first aircraft rolled off the assembly line. Delivery of the first F-16 is approximately two years behind schedule. An October 2024 MND report to the Legislative Yuan cited software problems and other development bottlenecks as the main culprit for delays.
Although the first F-16 has now finished assembly, I have elected to not mark this sale as being partially delivered. The October 2024 MND report and March 2025 reports from Taiwan’s Central News Agency and Taipei Times mention that there will be some gap between the new aircraft being produced and their delivery to Taiwan. This probably is because the aircraft will need to undergo some final flight testing and perhaps pilot training in the United States. Until the first F-16 Block 70/72 lands on Taiwan’s territory, I will not consider this sale to be partially delivered.
The Taiwan Security Monitor will continue keeping tabs on the F-16, HCDS, and all other arms sales in the backlog.
For the full dataset, click below: