Article (gold) is tops for typically shrewd speculators (9)
I believe the answer is:
theorists
'speculators' is the definition.
(I've seen this before)
'article gold is tops for typically shrewd' is the wordplay.
'article' becomes 'the' (the definite article).
'gold' becomes 'or' ('or' is the heraldic name for gold).
'tops for' suggests taking the first letters (in a down clue, the tops are the top letters).
The first letters of 'typically shrewd' is 'ts'.
'the'+'or'+'is'+'ts'='THEORISTS'
(Other definitions for theorists that I've seen before include "speculators" , "those who speculate" .)