There is no single industry ranking, but among the leading core banking software companies are Temenos, FIS, Oracle FLEXCUBE, Finacle, Finastra, Mambu, Thought Machine, Fiserv, Jack Henry, and 10x Banking. Other notable providers include Finxact, Nymbus, Skaleet, Tuum, SDK.finance, and Kindgeek. It depends on factors such as institution size, deployment model, and customization requirements.