PMI is the institute that sets standards for Program/Project Management.
The Software Engineering Institute (SEI) has established capability maturity models which are used to demonstrate performance at levels 1-5.
Most companies reach to achieve Level 3, however many are recognized as high as Level 5.
To achieve these levels, a company must have an external assessment performed by a certified SEI representative.
Regards
Peter Buitenhek
ProfitDeveloper.com