It limits the field to insure against betting losses (5)
I believe the answer is:
hedge
This clue could be a double definition.
'it limits the field to insure against betting' is the first definition.
The definition suggests a singular noun which matches the answer.
'losses' is the second definition.
The answer and definition can be both related to property as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
Can you help me to learn more?
(Other definitions for hedge that I've seen before include "Fence formed by bushes" , "Boundary plant row" , "Fence of bushes or small trees" , "Minimise risk" , "appear non-committal in statement" .)