Claim to have in one's possession (4)
I believe the answer is:
hold
This clue could be a double definition.
'claim' is the first definition.
(thesaurus)
'have in one's possession' is the second definition.
'hold' can be an answer for 'possession' (thesaurus). I'm unsure of the 'have in one's' bit.
'to' is the link.
Can you help me to learn more?
(Other definitions for hold that I've seen before include "Grip" , "Keep in one's grasp" , "Maintain" , "Keep; cargo space" , "Have or possess" .)