| SIAM LIMITED | Private company limited by shares | Live |
| SIAM GAS HK LIMITED | Private company limited by shares | Live |
| Chi Wa Siam Limited | Private company limited by shares | Live |
| SPA SIAM LIMITED | Private company limited by shares | Live |
| SIAM INVESTMENT ADVISORS LIMITED | Private company limited by shares | Dissolved |
| Siam Asia Limited | Private company limited by shares | Live |
| SIAM CANADIAN (ASIA) LIMITED | Private company limited by shares | Live |
| Siam Film Associates Limited | Private company limited by shares | Live |
| SIAM SPA & BEAUTY LIMITED | Private company limited by shares | Dissolved |
| CAFE SIAM LIMITED | Private company limited by shares | Dissolved |
| SIAM CANADIAN (CHINA) LIMITED | Private company limited by shares | Dissolved |
| SIAM CLOTHING HK LIMITED | Private company limited by shares | Live |
| Siam Air Transport Co., Limited | Private company limited by shares | Live |
| SIAM COMMERCIAL FINANCE LIMITED | Private company limited by shares | Dissolved |
| Siam Bay Designs Company Limited | Private company limited by shares | Dissolved |
| SOUTH EAST ASIA TRADING COMPANY (SIAM) LIMITED | Private company limited by shares | Live |
| SIAM EXPRESS LIMITED | | Live |
| SIAM FOODTRADE LIMITED | Private company limited by shares | Live |
| Siam Group Limited | Private company limited by shares | Live |
| SIAM PROPERTIES SALES GROUP, LIMITED | Private company limited by shares | Dissolved |
| SIAM INFRASTRUCTURE LIMITED | Private company limited by shares | Dissolved |
| Le Siam Internetwork Company Limited | Private company limited by shares | Live |
| SIAM SUCCESS INVESTMENT LIMITED | Private company limited by shares | Dissolved |
| SIAM INVESTMENTS LIMITED | Private company limited by shares | Dissolved |
| Siam Thai (Jordan) Massage & Spa Limited | Private company limited by shares | Live |
| SIAM CAPITAL DEVELOPMENTS (HONG KONG) LIMITED | Private company limited by shares | Dissolved |
| SIAM LIFESTYLE LIMITED | Private company limited by shares | Live |
| SIAM MAO Magic Limited | Private company limited by shares | Live |
| AEC Siam Finance and Investment Management Co., Limited | Private company limited by shares | Live |
| Siam Investment Management Limited | | Live |
| SIAM MATE LIMITED | Private company limited by shares | Live |
| Siam Thai Noodles BBQ Company Limited | Private company limited by shares | Live |
| SIAM PACIFIC COMPANY LIMITED | Private company limited by shares | Live |
| Siam Private Equity Limited | Private company limited by shares | Live |
| SIAM PRODUCTIONS TRADING LIMITED | Private company limited by shares | Live |
| SIAM PRODUCTS LIMITED | Private company limited by shares | Dissolved |
| SIAM PROPERTY LIMITED | Private company limited by shares | Live |
| Siam Property Direct Limited | Private company limited by shares | Live |
| ROYAL SIAM (ASIA) LIMITED | Private company limited by shares | Dissolved |
| SIAM SHOE LIMITED | Private company limited by shares | Dissolved |
| SIAM STAR COMPANY LIMITED | Private company limited by shares | Live |
| STAR OF SIAM (HONG KONG) LIMITED | Private company limited by shares | Dissolved |
| Siam Success Limited | Private company limited by shares | Dissolved |
| SUPER SIAM (HONG KONG) LIMITED | Private company limited by shares | Live |
| SIAM TECHNOLOGIES COMPANY LIMITED | Private company limited by shares | Dissolved |
| SIAM TECHNOS CO., LIMITED | Private company limited by shares | Live |
| Siam Thai Massage & Spa Limited | Private company limited by shares | Live |
| Siam sense Thai massage Limited | Private company limited by shares | Live |
| SIAM ORCHID THERAPY LIMITED | Private company limited by shares | Dissolved |
| SIAM THIDA LIMITED | Private company limited by shares | Dissolved |
| SIAM TRADING COMPANY LIMITED | Private company limited by shares | Dissolved |
| SIAM TRADING LIMITED | Private company limited by shares | Live |
| Siam Sister Trading Limited | Private company limited by shares | Live |
| Siam Air Transport Company Limited | | Live |
| Siam Villa Limited | Private company limited by shares | Live |
| SIAMAMA RESTAURANTS LIMITED | Private company limited by shares | Live |
| Siam.Digital Limited | Private company limited by shares | Live |
| Siamease e-shopper Company Limited | Private company limited by shares | Dissolved |
| SIAMERICAN FUND, LIMITED -THE- | Private company limited by shares | Dissolved |
| SIAMERICAN SECURITIES LIMITED | Private company limited by shares | Dissolved |
| SIAMESE AND CHINESE ANTIQUES CO. LIMITED | Private company limited by shares | Dissolved |
| Issaya Siamese Club Limited | Private company limited by shares | Live |
| Siametal Resource Limited | Private company limited by shares | Live |
| Siamgate HK Limited | Private company limited by shares | Live |
| SIAMO TRADING CO., LIMITED | Private company limited by shares | Dissolved |
| Siamonoi Limited | Private company limited by shares | Live |
| SIAM-TEC LIMITED | Private company limited by shares | Live |