1. Caterpillar Inc.
2. General Electric Company (GE)
3. MAN Energy Solutions SE
4. Siemens AG
5. W?rtsil? Corporation
6. Rolls-Royce Holdings plc
7. Doosan Engine Co. Ltd.
8. Cummins Inc.
9. Yanmar Co. Ltd.
10. Mitsubishi Heavy Industries
Ltd. (MHI)