April 2024 was a relatively quiet month for the US arms backlog to Taiwan. Congress did not receive any notifications of new arms sales, and there were no reports of US weapons being delivered to Taiwan that would reduce the backlog. On April 24, President Biden signed into law an emergency supplemental appropriations bill that might help clear some of the backlog, but it depends on how the funds are used.

As of the end of April 2024, the Taiwan arms sale backlog amounted to approximately $19.7 billion, a $520 million increase from our March 2024 update. Figure 1 shows the current breakdown of the arms backlog by weapon category, and Figure 2 shows how the backlog has changed from March to April 2024.

The $520 million increase is the dollar value of 18 additional High Mobility Artillery Rocket Systems (HIMARS), support vehicles, and munitions that were tacked onto an October 2020 sale of 11 HIMARS launchers.

Taiwan’s Ministry of National Defense (MND) announced the additional HIMARS purchase in May 2023. However, we could not locate an arms sale notification in the Congressional Record around the time of MND’s announcement. Our earlier updates to the backlog data set included the HIMARS plus-up without an assigned dollar value. However, in April we located the HIMARS arms sale notification in the December 5, 2022, edition of the Congressional Record while reviewing information about another arms sale.

Reaching an accurate estimate of the US arms sale backlog to Taiwan has been challenging. Data on both arms sales and deliveries exist, but not in one place. Now that we have tracked down the cost information for the HIMARS plus-up, we are confident that we have accurate data on all backlogged arms sales to Taiwan. Table 1 shows an itemized list of all arms sales in the backlog.

The arms backlog may begin declining in the near future.

The emergency supplemental appropriations bill contains $1.9 billion available until September 2025 to replenish US military stockpiles of equipment transferred to Taiwan. In the Taiwan Enhanced Resilience Act of 2022, Congress authorized a $1 billion per year ceiling for Presidential Drawdown Authority (PDA), which pulls equipment out of US military stockpiles for immediate transfer to a foreign country. However, without appropriations to replenish transferred equipment, there was little incentive for the administration to use PDA. In 2023, the Biden administration only sent $345 million worth of equipment to Taiwan via PDA, and it did not disclose what capabilities it sent.

The emergency supplemental should lead to more PDA transfers to Taiwan because the US military now has the funds necessary to backfill the equipment it sends. PDA transfers could be an excellent tool for rapidly decreasing the size of the arms sale backlog, but currently there is simply too much uncertainty around how the US military will use the new appropriations to predict what will happen. Hopefully the administration will provide detailed information on any future PDA transfers to Taiwan, as they have for PDA transfers to Ukraine.

Download our Taiwan arms backlog data from April 2024.