Stake in a buoyant economy (4)
I believe the answer is:
ante
'stake' is the definition.
(I've seen this before)
'in a buoyant economy' is the wordplay.
'in' indicates a hidden word.
'ANTE' is hidden in the letters of 'buoyant economy'.
(Other definitions for ante that I've seen before include "Stake put up by a poker-player before receiving cards" , "Pre-deal stake" , "Stake put up before the deal" , "Preceding birth" , "Poker-player's stake before the deal" .)