On March 11, 2024, the Stockholm International Peace Research Institute (SIPRI) released an annual update to its Arms Transfers Database, which is the primary data source that our arms backlog dataset uses to track US weapon deliveries to Taiwan.
As shown in Figure 1, the SIPRI database update brings the current backlog of US arms sales to Taiwan to at least $19.17 billion—$66 million higher than our February 2024 update. See the tabs in Figure 2 to compare the February and March versions of backlog.
There were no new US arms sales to Taiwan announced in March 2024. Instead, the change in value from last month is due to new information about previous sales.
Removing Torpedoes, Adding Anti‐Tank Missiles
For the March 2024 update to the Taiwan arms backlog dataset, we removed a 2017 sale of lightweight torpedo conversion kits while adding a 2019 sale of TOW-2B anti‐tank guided missiles.
In June 2017, the Defense Security Cooperation Agency (DSCA) announced a $175 million sale of equipment to upgrade 168 MK-46 Mod 5 lightweight torpedoes to the MK-54 configuration. This sale is coded in our dataset as a munition. These torpedoes are launched from aircraft and warships to attack enemy submarines. Besides the initial DSCA announcement, there was very little publicly available information on the lightweight torpedo sale. Even the 2023 edition of SIPRI’s Arms Transfers Database did not include any information on these torpedoes.
The 2024 update to SIPRI’s Arms Transfers Database indicates that the final delivery of the lightweight torpedo conversion kits occurred sometime in 2022. Based on this new information, we have marked this sale as completed and removed it from the arms backlog, reducing the backlog’s value by $175 million.
However, this reduction in the arms backlog dataset is offset by an addition. On July 8, 2019, DSCA notified Congress that it was modifying a 2015 sale of TOW-2B anti‐tank guided missiles to add 1,240 missiles and associated equipment valued at $241 million. Based on the other equipment mentioned in the arms sale announcement, these TOW missiles will likely be mounted to relatively light military vehicles, like Humvees, to improve their anti‐armor capabilities. We code the TOW missiles as an asymmetric capability instead of munitions, as the sale includes other equipment in addition to the missiles.
We should have captured the additional TOWs in our January 2024 update because that is the first update that uses the Congressional Record as a data source. The mistake came to our attention when we reviewed SIPRI’s new data, which prompted us to double‐check the Congressional Record and locate the TOW notification. However, these additional TOWs will not be in the backlog for long. Reporting from last year citing Taiwan’s Ministry of National Defense indicates that delivery of the missiles should occur sometime this year.
To sum up, based on SIPRI’s new data, we removed a $175 million sale of lightweight torpedo conversion kits from the backlog and added a $241 million sale of TOW anti‐tank missiles, which increased the overall value of the US arms backlog to Taiwan by $66 million. As with other updates to our data, these additions and subtractions result from new information coming to light rather than newly announced sales or recent deliveries. Table 1 contains the itemized composition of the backlog.
Deliveries in Progress
The new SIPRI data include some interesting details about the arms backlog that are worth mentioning.
Our January 2024 arms backlog update mentioned that Taiwan purchased 18 additional HIMARS launchers after canceling an order of Paladin mobile howitzers. According to SIPRI’s data, this modification also included a purchase of 864 guided rockets, which would be a major boost to Taiwan’s asymmetric capabilities. Unfortunately, SIPRI does not mention a dollar figure for the rockets or additional HIMARS launchers.
There are three arms sales in the backlog that SIPRI reports as partially delivered. Three of six MS-110 aircraft reconnaissance pods, sale announced in October 2020, were in Taiwan’s hands by the end of 2023. Taiwan also received its first two Abrams tanks in 2022, likely for initial familiarization and training before the remaining 106 tanks arrive in tranches between 2024 and 2026. Finally, Taiwan received five MK-48 heavyweight torpedoes in 2023. According to SIPRI, the remaining 41 torpedoes should be delivered by 2026.
Thus far, our arms backlog dataset has removed items once final delivery is complete rather than trying to partially reduce dollar amounts based on partial delivery. We will continue using this method, but the SIPRI update does provide a look at partial deliveries that we do not typically see.
