| SEIC | Strategic Economic Investment and Commercialization (board) | 战略经济投资和商业化（董事会） |
| SEIC | Sakhalin Energy Investment Company (Russia) | 萨哈林能源投资公司（俄罗斯） |
| SEIC | System Engineering and Integration Contractor | 系统工程与集成承包商 |
| SEIC | Shipboard Environmental Information Clearinghouse | 船舶环境信息交换所 |
| SEIC | Safety Education and Instruction Council | 安全教育和指导委员会 |
| SEIC | S E I Investment Corporation | S E I投资公司 |