ASE Technology
ASX · NYSEThe world's largest independent chip packaging company, and the pressure valve TSMC leans on when its own CoWoS lines run out of room.
Who they are
Brothers Jason and Richard Chang founded Advanced Semiconductor Engineering in Kaohsiung, Taiwan in 1984, at a time when chipmakers mostly packaged and tested their own chips in-house. ASE bet that a specialist could do it better and cheaper, the same "outsource the unglamorous step" logic that made TSMC's foundry model work a few years earlier. That bet paid off: ASE overtook Amkor in 2003 to become the world's largest packaging and testing provider, and in 2018 it merged with rival Siliconware Precision Industries (SPIL) and electronics manufacturer USI to form ASE Technology Holding, the entity that trades today. Jason Chang remains chairman, with longtime COO Tien Wu running day-to-day operations.
What they do
ASE is what the industry calls an OSAT — an outsourced semiconductor assembly and test provider — holding roughly 19% to 44.6% of that market depending on how narrowly it's measured, and its own VIPack advanced packaging platform (covering 2.5D/3D IC stacking, FOCoS-Bridge, and integrated optics) puts it in direct competition with TSMC's in-house CoWoS process for the same AI chip customers. In practice, ASE plays two roles at once in this chain: it's an independent packaging option for customers who don't want to queue behind Nvidia at TSMC, and it's also an overflow contractor TSMC itself has reportedly leaned on for some packaging steps when its own CoWoS capacity runs short.
How ASE makes money
Packaging and testing service fees, billed per chip processed, plus a smaller electronic manufacturing services (EMS) business inherited from the USI merger. The AI buildout has been unambiguously good for the top line: trailing twelve-month revenue reached roughly $21.7 billion as of Q1 2026, and ASE raised its own 2026 capital expenditure guidance to a record $8.5 billion specifically to chase advanced packaging demand. Nearly 70% of group revenue now comes from customers in the US and Europe — a reminder that even though the physical work happens in Taiwan, the demand is overwhelmingly American AI capex flowing through.
The bigger trend
ASE's new K28 plant, breaking ground in October 2024 and targeted for completion in 2026, exists specifically to expand advanced CoWoS-style packaging and testing capacity — the clearest possible signal that ASE sees the packaging bottleneck as a multi-year opportunity rather than a temporary squeeze. The company has also been buying its way into more capacity outright, including plans to acquire Analog Devices' Malaysian subsidiary and a Kaohsiung fab purchase from Win Semiconductors, both aimed at the same AI/HPC packaging expansion.
Whether ASE's advanced packaging capacity actually comes online fast enough to meaningfully relieve TSMC's CoWoS bottleneck, or whether it mostly ends up serving customers who were never going to get TSMC allocation in the first place. Also worth tracking: ASE's roughly 70% revenue exposure to the US and Europe means any slowdown in American hyperscaler capex would hit ASE's order book faster than most of its Taiwanese semiconductor peers.
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Frequently asked questions
OSAT stands for Outsourced Semiconductor Assembly and Test — a company that packages and tests chips on behalf of chip designers and foundries, rather than designing or fabricating the silicon itself. ASE is the world's largest OSAT provider.
Partly. ASE competes with TSMC's in-house CoWoS packaging for the same advanced-packaging customers, but it also serves as an overflow partner TSMC itself has reportedly relied on when its own packaging capacity runs short, making the relationship both competitive and complementary.
ASX is the ticker for ASE Technology's American Depositary Receipt, traded on the NYSE. The underlying ordinary shares trade on the Taiwan Stock Exchange under the ticker 3711.
This page describes public value-chain positioning for informational purposes only. It is not investment advice, and inclusion here is not a recommendation to buy or sell any security. Figures reflect public reporting as of mid-2026 and may have changed since.