Q: Do co-applicants have to sign a statement of joint intent?
A: Under Regulation B, joint applications are reviewed for some evidence that the application file reflects an applicant's intention to apply for joint credit. Co-applicants are applicants who applied for credit contemporaneously with another applicant and do not include those who agreed to become an applicant after the application was submitted because the original applicant did not qualify for the loan on their own. As a result, whether a co-applicant must indicate joint intent depends on whether they were in fact co-applicants.
Regulatory guidance on joint intent can be found in staff commentary to 12 CFR 1002.7(d). Also, Regulation B's Appendix B contains model application forms that provide examples of how joint intent can be evidenced on an application form. This information may be found here: https://www.ecfr.gov/current/title-12/chapter-X/part-1002