Pleased to hold rental agreement (5)
I believe the answer is:
lease
'rental agreement' is the definition.
(eg rental agreement for a flat)
'pleased to hold' is the wordplay.
'to hold' indicates a hidden word (I've seen 'holding' mean this).
'LEASE' is hidden within 'pleased'.
(Other definitions for lease that I've seen before include "Summer's has too short a date (Shak.)" , "Let out, hire" , "Tenancy agreement" , "Property rental agreement" , "Renting contract" .)