Crossword Genius

Firm keeping nothing in store (5)

Ross

I believe the answer is:

'store' is the definition.
(hoard is a kind of store)

'firm keeping nothing' is the wordplay.
'firm' becomes 'hard' (both can mean durable or strong).
'keeping' is an insertion indicator.
'nothing' becomes 'o' (looks like zero - 0).
'hard' going around 'o' is 'HOARD'.

'in' is the link.

(Other definitions for hoard that I've seen before include "One's savings", "Squirrel away", "Collection", "accumulated wealth", "Hidden stock".)

I've seen this clue in The Sun.