Do financiers request IDERA's for small aircraft, or just large ones registered under the CTC?
Firstly just a little bit of background. IDERA's - Irrevocable Deregistration and Export Request Authorizations - are issued under the Cape Town Convention (or Cape Town Treaty). This is a voluntary convention that countries can subscribe to. It essentially provides more assurance for financiers, who can therefore provide lower interest rates to aircraft buyers.
The FAA states the eligibility requirements for IDERA's, which, for fixed-wing aircraft, need to be able to carry at least 8 people, or can carry goods in excess of 2750 kilograms (6050 pounds). So most aircraft considered 'small' probably would not be covered.