Page 44 - Data Field 63 - 9999 is a valid entry when there is no co-applicant. Page 75 - b. Use Code 9999 in the co-applicant field if there are no co-applicants or co-borrowers. Page 20 of the GIR -  Code 9999â€"No co-applicant NOTE: Use Code 9999 in the co-applicant field if there are no co-applicants or co-borrowers.