DBD Director-General Poonpong Naiyanapakorn said the department had identified 6,551 foreign-owned legal entities across Thailand considered at risk of violating the Foreign Business Act B.E. 2542 (1999).
The investigation focuses on companies where foreigners hold 50% or more of shares and are suspected of operating businesses without the required permissions under Thai law.
Bangkok ranked highest with 3,934 high-risk entities, followed by Chonburi with 1,084 and Samut Prakan with 413. Phuket ranked eighth with 68 entities identified as high risk.
Authorities said particular attention is being paid to businesses operating in tourist and economic zones, especially sectors where Thai nationals are considered not yet ready to compete or where foreign ownership is restricted under the Foreign Business Act.
The businesses under greatest scrutiny include real estate trading, with 217 entities flagged nationwide, and restaurant and food service operations, with 204 entities under investigation.
The DBD warned that if investigations uncover illegal land ownership or income generated from land rentals without proper authorisation, cases will immediately be forwarded to the Land Department for legal action.
Mr Poonpong said the department is also targeting the wider support network behind nominee operations, including accountants, auditors and accounting firms suspected of helping conceal business ownership structures or create false nominee arrangements.
“If accounting firms, accountants or auditors are found to have assisted in concealing businesses or structuring nominee accounts, strict legal action will be taken,” he said, adding that cases would also be referred to professional ethics committees for maximum disciplinary penalties.
The operation is being conducted jointly with the Department of Special Investigation (DSI), the Royal Thai Police and tax authorities.
The DBD reiterated warnings to Thai nationals not to assist foreigners in establishing nominee businesses, noting that both operators and accomplices face severe penalties under the Foreign Business Act.
Violations can carry penalties of up to three years’ imprisonment, fines ranging from B100,000 to B1 million, or both.
Mr Poonpong explained that the Foreign Business Act divides restricted activities into three categories.
The first covers businesses absolutely prohibited to foreigners, including rice farming, fishing in Thai waters and land trading. The second includes businesses linked to national security, culture or natural resources, which require Cabinet approval. The third covers businesses in which Thai operators are considered not yet ready to compete, such as tourism, hotels, retail, wholesale and professional service businesses.
The department said it is using linked databases and risk-analysis technology to screen suspicious legal entities and expand investigations into related business networks.
Separately, the DBD also released updated nationwide business registration statistics following a major cleanup of its legal entity database.
As of May 4, Thailand had 2.08 million registered legal entities in total, including partnerships, limited companies and public companies.
Of those, 992,890 businesses remain active, while 397,463 have ceased operations and 649,992 have been struck off the registry as dormant after failing to submit financial statements or showing no registration activity for three consecutive years.
The DBD urged businesses and investors to carefully verify the status, financial statements and shareholder structures of legal entities before conducting transactions, warning that fraudsters may use inactive or dissolved companies to deceive investors.
Business information can be checked through the DBD DataWarehouse+ system on the department website.