When there is insufficient SFA for entitled Service personnel, DIO will issue a Non-Availability Certificate (NAC) which is the authority to obtain SSFA. DIO work with the MOD Contractor to secure SSFA from the commercial rental market. Applicants who are in receipt of a NAC will be provided with further guidance from DIO at the point of issue. The policy regarding SSFA is in JSP 464 Vol.1 Part 1 Section 5.