While there are several accreditation boards for Lean Six Sigma. Some have a long history, and some are newly formed. Some accreditation boards like Exemplar Global have been around for long and have a large number of certified professionals, thus providing a large fraternity network.
The value of Lean Six Sigma certification is better understood by studying the list of corporate clients who patronize it. When large successful organizations agree to get a program conducted repeatedly at their premises, it shows that the program is valued by business world.