M-form

The M-form (Multidivisional form) refers to an organizational structure by which the firm is separated into several semi autonomous units which are guided and controlled by (financial) targets from the centre. In the 1920s, the multidivisional structure was a major organizational innovation that occurred first in the USA. Most large American multiproduct firms adopted this structure before World War II. Most large European multiproduct firms followed in the 1950s and 1960s.

References

http://www.encyclopedia.com/doc/1O18-Mform.html