Odds on copper delivering a point of transition (4)
I believe the answer is:
cusp
'a point of transition' is the definition.
(I've seen this in another clue)
'odds on copper' is the wordplay.
'odds' becomes 'sp' (betting abbreviation for starting price).
'on' says to put letters next to each other.
'copper' becomes 'cu' (Cu is the chemical symbol for copper).
'sp' put after 'cu' is 'CUSP'.
'delivering' is the link.
(Other definitions for cusp that I've seen before include "Prominence on a tooth" , "Point where two curves meet - point of transition" , "Either point of a crescent moon" , "Point (e.g. of tooth)" , "Turning point on which important developments depend" .)