Yes, they have their own data centers. They tend to be smaller since they don't have demand for 100K servers in any one city.
Weirdly, IBM's map seems to have disappeared but here's Oracle: https://www.oracle.com/cloud/architecture-and-regions.html
Weirdly, IBM's map seems to have disappeared but here's Oracle: https://www.oracle.com/cloud/architecture-and-regions.html