Rough calculation puts total possessions about one million (8)
I believe the answer is:
estimate
'rough calculation' is the definition.
(I've seen this before)
'total possessions about one million' is the wordplay.
'total possessions' becomes 'estate' (I've seen this before).
'about' indicates putting letters inside.
'one million' becomes 'im' (I've seen this in other clues).
'estate' placed around 'im' is 'ESTIMATE'.
'puts' is the link.
(Other definitions for estimate that I've seen before include "Approximate calculation" , "Rough cost" , "rough judgment" , "Judgement of approximate value or size" , "Form opinion of - tea times (anag)" .)