Commercial property assumptions (8)
I believe the answer is:
premises
This clue is a double definition.
'commercial property' is the first definition.
(eg business premises)
'assumptions' is the second definition.
('premise' can be a synonym of 'assumption')
(Other definitions for premises that I've seen before include "Assumptions" , "Property" , "Business buildings" , "A business's site and buildings" , "establishment" .)