Which are the top 10 IT service companies worldwide?

The top 10 IT service companies worldwide, based on various factors such as revenue, market share, and global presence, include:

1. IBM
2. Accenture
3. TCS (Tata Consultancy Services)
4. Cognizant
5. Infosys
6. DXC Technology
7. Wipro
8. HCL Technologies
9. Capgemini
10. NTT Data

Please note that rankings may vary depending on different sources and criteria used for evaluation.