Managed by (5)
I believe the answer is:
under
'managed by' is the definition.
(as in working 'under' a supervisor or manager)
This is the entire clue.
(Other definitions for under that I've seen before include "See 16 Down" , "Beneath or subordinate to" , "'Beneath, below (5)'" , "In the process of" , "Dylan Thomas radio play ''.... Milk Wood''" .)