Those people hold gold as a speculation (6)
I believe the answer is:
theory
'a speculation' is the definition.
(I've seen this before)
'those people hold gold' is the wordplay.
'those people' becomes 'they' (I've seen this in other clues).
'hold' indicates putting letters inside.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'they' placed around 'or' is 'THEORY'.
'as' is the link.
(Other definitions for theory that I've seen before include "The words, as opposed to the practice" , "Idea to explain something, say evolution" , "Speculative view" , "General principles of a subject" , "Thought" .)