The answer is yes and no. Yes you may have a non-occupant coborrower (NOCB) on a FNMA loan, but their income will not count towards meeting your ratios. When run through Fannie Mae's automated underwriting system (DU) it analyzes the risk factors in the loan casefile without the benefit of the non-occupant coborrowerâ€™s income or liabilities. Only a "manually underwritten" FNMA mortgage can benefit from a NOCB's income and no one is doing those.
What you need to do if you need your parent's income is to find a lender or seasoned loan officer who will know to place your loan with a Freddie Mac lender which will indeed count that income towards your ratios. When running it through Freddie's automated system (LP) it will include the NOCB's income towards meeting your debt ratio.
FHA will also allow a NOCB's income to count towards your debt ratio.
Please contact me for assistance.