Investing in Thai PCB plants: BOI incentives and what the money buys

Since 2023, printed circuit board (PCB) makers, mostly from China, Taiwan, Hong Kong and Japan, have filed more than 200 applications for Thai investment promotion. The Board of Investment (BOI) puts PCB and PCB-material applications for 2023 to 2025 at 222 projects worth 320,078 million baht, and says Thailand is now the largest PCB producer in ASEAN and fifth in the world.^[1] This article explains the incentives, what that figure measures, the largest projects, what the money buys and the risks.

In brief

• The BOI figures count applications, not money spent.^[2]
• HDI and large flexible or multilayer projects can get an eight-year tax holiday capped at the investment; a plain PCB project gets none.^[3]
• The largest reported project is the Zhen Ding Technology (ZDT) joint venture in Prachin Buri: more than 65,000 million baht approved.^[4]
• Parent filings show slow ramp-ups and early losses at new Thai plants.^[5][6]

What the BOI offers a PCB project

BOI incentives are set per activity. By mid-2024 the BOI had widened the PCB list to cover the whole chain, from fabrication and assembly to raw materials, components and services.^[7] The 2026 BOI guide sets the PCB activities as follows.^[3]

The group sets the corporate income tax (CIT) exemption: eight years for A2, five for A3, three for A4 and none for B. For A2 to A4 the exempt amount is capped at 100 percent of the project's investment. Every group, including B, gets import-duty exemptions on machinery and some raw materials, and non-tax rights such as land ownership and work permits for foreign experts.^[3] A3 and A4 projects in BOI-promoted industrial estates or zones get one extra year; A2 projects do not. Spending on R&D, advanced training or local suppliers can add years, up to 13 in total for groups A1+, A1 and A2.^[3]

Aoshikang reports that its Thai subsidiary's BOI certificate exempts profits for up to eight years, with the total exemption limited to the project's actual investment, excluding land and working capital.^[6]

Two changes reduce the value of a tax holiday for the largest investors. The OECD global minimum tax has applied since 1 January 2025: groups with revenue above 750 million euros must pay at least 15 percent, so profit exempted by a BOI holiday can still attract a top-up tax. The BOI expects about 1,500 companies in Thailand to be affected and is preparing refundable tax credits (QRTC) tied to R&D, skills and similar spending.^[8] ZDT, for example, reports revenue above 180,000 million baht a year, far above the threshold.^[4] Then in September 2026 the BOI said it would phase out tax breaks for low-margin operations and judge success by realised investment rather than application volume.^[9]

Do incentives decide where a plant goes? Rarely. An OECD review of Southeast Asia cites surveys in which more than 80 percent of investors in Thailand and Viet Nam would have invested without incentives, and notes that tax holidays favour the most profitable firms.^[10] A study of more than 40 countries found that longer tax holidays attracted foreign direct investment in Latin America and the Caribbean, but that no tax incentive raised total private fixed investment.^[11] Our reading, in line with the OECD's view that incentives matter most between shortlisted locations: for a PCB project the BOI package lowers cost at the final choice of site; it is not the reason to choose Thailand.^[10]

How much money: reading the BOI numbers

Five different amounts circulate for the same project, and they should not be mixed.

1. Announced: what a company says it plans, often over many years.
2. Applied: the investment stated in a BOI application. All the PCB totals below are of this kind.
3. Approved: projects the BOI board or its subcommittee has accepted.
4. Certified: approved projects that have received a promotion certificate. Of the first 25 fast-tracked projects, all approved, 19 had certificates by September 2026.^[9]
5. Invested: money spent on buildings and machinery, which the BOI now tracks each quarter.^[2]

The BOI has published its PCB application totals for moving windows and changing scopes.

Three readings are safe. First, the jump is real: applications averaged 15,750 million baht a year in 2021 and 2022, then passed 100,860 million baht in 2023 alone.^[12] Over 2023 to 2025 they averaged about 106,700 million baht a year, nearly seven times the earlier level (calculated here from the BOI totals).^[1] Second, the totals cannot be differenced into annual figures, because windows and scopes differ. Third, new applications appear to have slowed: the project count moved from 222 at the end of 2025 to 224 by mid-2026.^[1][17] The BOI has not published a PCB-only figure for 2026, so this is an inference from two totals whose scopes may differ.

Dollar figures need the same care. The BOI gave the same 331,000 million baht as USD 9.85 billion on 3 August 2026 and as more than USD 10.1 billion on 26 August 2026, the second at the Bank of Thailand average selling rate of about 32.8 baht per dollar.^[17][18] At that rate the 320,078 million baht for 2023 to 2025 is about USD 9.8 billion (calculated here). Otherwise this article keeps amounts in the source currency.

Spending lags applications. The BOI reports realised investment of more than 127,000 million baht in the second quarter of 2026 across AI-linked industries, a group that includes PCBs alongside optical transceivers, hard disk drives and digital infrastructure; it does not separate PCBs.^[2] At project level, Suntak Technology puts the first phase of its Prachin Buri plant at about RMB 1 billion; by 30 June 2026 it had spent 8.45 percent of its RMB 800 million Thai construction budget, and it expects the first phase to be built in the first quarter of 2027.^[19]

The largest reported projects

ZDT shows how amounts grow between announcement and approval. In January 2024 the partners described a first phase of about 10,000 million baht and more than 50,000 million baht by 2030.^[22] Two years later the BOI had approved four projects worth more than 65,000 million baht, with 5,600 Thai jobs planned.^[4]

Compeq shows how amounts get restated. When its plant opened in December 2024, the BOI gave a first-phase investment of 10,417 million baht on 112 rai, for multilayer boards of up to 34 layers, more than 90 percent exported, with about 600 jobs rising to more than 1,500.^[14] In May 2026 the BOI gave the first phase as 13,000 million baht, without explaining the difference.^[1] Compeq's own site lists the Thai plant with 1,400 employees.^[23]

The May 2026 second phases of Compeq, Multi-Fineline and Gold Circuit add 22,200 million baht to about 35,000 million baht of first phases, and more than 5,000 jobs to the 7,000 already hired.^[1]

What the money buys

Capacity. Few projects publish capacity next to cost. Advanced Interconnection Technology plans about 360,000 square metres a year, or about 30,000 square metres a month, for about 3,889 million baht.^[21] That is roughly 10,800 baht of investment per square metre of annual capacity (calculated here). It varies with product mix, so it is an illustration, not a benchmark.

Jobs. The BOI attaches jobs to approvals: 5,600 at ZDT and more than 12,000 across Compeq, Multi-Fineline and Gold Circuit after both phases.^[4][1] In 2024 the Thai Printed Circuit Association (THPCA) projected that about 50 more BOI-backed plants could lift Thailand's share of world circuit-board output from 4 percent to 10 percent and create 50,000 to 80,000 jobs. That is an industry projection, not a count.^[12]

Technology. The incentive design rewards the harder boards.^[3] The big approvals sit in that tier: ZDT's projects cover multilayer, flexible, substrate-like and HDI boards; Compeq makes multilayer boards of up to 34 layers; Gold Circuit makes multilayer and HDI boards.^[4][14][1]

Output. David Bergman of the Global Electronics Association, speaking at a BOI forum, put Thailand's PCB output at more than USD 5 billion in 2025.^[24] We found no official Thai production statistic for PCBs.

Plants. The MPBxChange register holds 39 researched PCB plants in Thailand: 33 reported operating or ramping, and 6 under construction or announced. Of the 39 that publish a founding year, 28 were registered in Thailand from 2022 onwards.

The BOI says most PCB plants are in Prachin Buri, Phra Nakhon Si Ayutthaya and Samut Prakan.^[15]

The supporting chain: laminate, glass fabric, foil and chemicals

Upstream materials qualify too: CCL, flexible CCL and prepreg projects can reach group A2.^[3] The BOI reported these materials projects in 2026.^[25][26]

In the BOI releases we reviewed from 2024 to 2026, none names a copper-foil or PCB-chemicals project. First Quality Circuit, a Chinese-owned fab in Rayong, told a trade journal in 2025 that core materials and high-end chemicals came mainly from China, and that its start-up costs ran 10 to 15 percent above levels in China.^[27]

Risks

Capacity arriving before orders. Nearly 60 Chinese and Taiwanese PCB makers set up factories in under three years, and Thai press in 2025 flagged volatile demand outside AI.^[28] Parent filings show the ramp-up problem. Dongshan Precision said in October 2025 that its flexible-board profit did not grow because new Thai capacity was underused.^[20] Shennan Circuits wrote in its 2026 interim report that customer qualification and product introduction take longer at its Thai plant than in China.^[5] Aoshikang's Thai subsidiary lost RMB 94.7 million in the first half of 2026.^[6] These show slow utilisation at individual plants, not proven sector-wide overcapacity; no source we reviewed publishes Thai utilisation rates.

Execution and permits. Imported materials, logistics and new teams raise start-up costs.^[27] The government's own remedy shows where delays occur: Thailand FastPass covers eight agencies, including Customs, the Department of Industrial Works and the power utilities, and aims to cut approval times by 20 to 50 percent.^[24] PCB plating produces metal-bearing wastewater, so treatment capacity and the factory licence sit on the critical path; the Rayong fab above has capacity to treat 1,500 tonnes of wastewater a day.^[27] We found no public case of a Thai PCB project stopped on environmental grounds, but the evidence is thin.

Labour. An executive at a PCB materials maker in Thailand told Nikkei Asia that pay for experienced production line managers had doubled in two to three years, to 80,000 to 100,000 baht a month from about 40,000 baht.^[29] ZDT's joint venture has signed curriculum agreements with five Thai universities to build its own pipeline.^[4]

Tariffs and origin. A US executive order of 31 July 2025 set Thailand's reciprocal tariff at 19 percent, with 40 percent for goods that US Customs finds were transshipped to evade duties.^[30] In February 2026 the US Supreme Court held that the emergency-powers law behind those reciprocal tariffs does not authorise tariffs,^[31] and from 24 July 2026 goods from Thailand carry a 12.5 percent tariff under Section 301.^[32] For boards made in Thailand from imported laminate and chemicals, origin records matter as much as the rate. Rates set by executive order change at short notice, so check the rate in force on the date of entry.

What this means

For buyers, the approvals mean more Thai HDI and high-layer capacity in 2026 and 2027, but qualifying a new plant takes time, so sourcing plans should allow for it. For investors, the 320,078 million baht^[1] is a record of intent; certificates issued, money spent and utilisation are the better measures, and the BOI and listed parents are starting to report them.

How this was researched

We read BOI press releases from 2024 to 2026 on the BOI's One Start One Stop site, the BOI Investment Promotion Guide 2026, half-year reports and investor records of listed parents in Shenzhen, company websites, a US executive order, Thai and trade press, and two research sources on tax incentives. The register is MPBxChange's list of researched PCB plants in Thailand, and its figures update as the list changes. Amounts are in the currency of each source, and conversions and ratios marked as calculated here are ours. Research was done on 24 September 2026.