November 20, 2025 [Hydrocarbon Processing]- Siam Cement plans to invest an additional $500 MM  in its Long Son Petrochemicals Complex, bringing the project’s total cost to $5.6 B. The expansion, slated for completion in 2027, reflects the company’s strategy to boost overseas operations amid a slump in domestic earnings. The Long Son facility, located in southern Vietnam, has recently increased its capacity utilization to over 85% following its August restart.

The company views Vietnam as a strategic growth engine, citing the country’s lower operating costs, strong economic trajectory, and extensive network of free trade agreements. Siam Cement has already invested around $7 billion across 28 projects in Vietnam and is shifting production of export-bound cement, building materials, and key chemical products to the country. At Long Son, half of the output will target major global markets—including China, Europe, and Australia—while the remainder will support domestic demand.

Despite its importance, the Long Son complex has been a drag on earnings, especially after a temporary shutdown last year caused by weak demand and depressed petrochemical prices. However, the company expects performance to improve significantly as the plant ramps up. The complex is projected to generate $1.5 billion in revenue by 2026 at full capacity and achieve positive cash flow by 2028, though a timeline for profitability has not been disclosed.

Siam Cement’s financial challenges continue to weigh on the company, highlighted by a third-quarter net loss of 669 million baht, compared with a profit in the same period a year earlier. The renewed focus on Vietnam underscores its broader strategy to stabilize earnings through geographic diversification and enhanced competitiveness in the global petrochemicals market.