Company embracing communist belief system (5)
I believe the answer is:
credo
'belief system' is the definition.
(I've seen this before)
'company embracing communist' is the wordplay.
'company' becomes 'co' (abbreviation).
'embracing' is an insertion indicator.
'communist' becomes 'red' (red is a kind of communist).
'co' going around 'red' is 'CREDO'.
(Other definitions for credo that I've seen before include "I believe in Latin" , "Dogma" , "Faith - I believe" , "Guiding beliefs" , "Part of the Latin Mass" .)