Who This Is For
Underwriters and underwriting managers, income QC reviewers, and heads of credit at lenders whose borrower mix includes retirees, disability recipients and anyone else paid by a benefit rather than a paystub. Also fair-lending officers, because retirement income is where age and income questions sit closest together.
One Benefit Check, Three Qualifying Incomes
Take an illustrative borrower who receives $2,400 a month in Social Security retirement benefits and has verified that all of it is nontaxable. Fannie Mae's General Income Information section, B3-3.1-01, lets the lender build an adjusted gross income by adding 25% of verified nontaxable income, provided the income and its tax-exempt status are likely to continue, and allows a larger amount if the borrower's actual tax rate supports it. That makes the qualifying figure $3,000. FHA's Handbook 4000.1 allows 15%, or more if the lender documents the borrower's actual tax liability, which makes it $2,760 at the default. The $240 difference is about $108 of monthly payment capacity at a 45% debt-to-income ratio.
That gap is real and it is legitimate, and it is one reason the Income Desk computes qualifying income separately for each program a file is being considered under, with the rule cited for each. A loan officer deciding between FHA and conventional for a borrower near the DTI limit should see both numbers and the reason they differ, rather than a single figure that silently assumed one program. Where files go wrong is the base the percentage is applied to.
The Gross-Up Applies to the Nontaxable Part, and Most Benefits Are Partly Taxable
Social Security is the clearest case. Depending on the borrower's other income, up to 85% of benefits can be federally taxable, so a borrower with a pension, IRA distributions or part-time wages often has a benefit that is only partly nontaxable. Grossing up the whole check overstates income. A second way to overstate it is to apply the gross-up once, early, and then carry the grossed figure into later calculations as if it were the raw amount, so it gets grossed up again.
The tax return answers the question directly, so that is where the agent reads it. On Form 1040, line 6a is total Social Security benefits and line 6b is the taxable amount. Lines 5a and 5b do the same for pensions and annuities, and lines 4a and 4b for IRA distributions. The agent extracts both lines of each pair, cites them to the page, and computes the nontaxable fraction from them. A pension where 5b equals 5a is fully taxable and gets no gross-up at all. A benefit where 6b is zero is fully nontaxable. Everything in between gets the gross-up on the nontaxable fraction only. When the return is missing, or the borrower's situation has changed since the return was filed (a spouse died, a pension started, wages stopped), the fraction from the old return may no longer hold, and the agent does not guess. It routes the question to the underwriter with the lines it read and the change that makes them unreliable.
The second protection is structural. In the Loan Graph, the raw benefit amount, the nontaxable fraction and the grossed-up figure are three separate fields, each cited, and the grossed figure is derived, never typed. The gross-up can only be applied to a raw amount, so applying it twice is not something the data model can represent. That one modeling choice closes off the double gross-up entirely, which is cheaper than catching it in review.
The Award Letter and the Deposit Will Not Match
The next most common mismatch is between what the Social Security Administration says it pays and what lands in the bank account. The award letter states the gross monthly benefit. The deposit is usually lower, because Medicare Part B premiums are withheld before payment, and sometimes because the borrower elected federal tax withholding. A reviewer comparing the two sees a discrepancy. The correct qualifying figure is the gross benefit, so the agent is written to expect the difference, explain it, and cite both documents. It flags the case where the deposit is higher than the award letter, or lower by more than a premium and elected withholding can explain, because that pattern can mean a garnishment, an overpayment recovery, or a letter that belongs to a different year.
Pensions have their own version: the pension statement shows a gross amount, and the deposit reflects withholding and sometimes health premiums. The same rule applies. Qualify on the documented gross, and explain the net.
Continuance Comes From Documents, Not From the Borrower's Age
Fannie's Annuity, Pension, or Retirement Income section, B3-3.4-03, requires lenders to document that distributions from a 401(k), IRA or similar account will continue for at least three years, and Fannie now measures three-year continuance from the note date. The agent computes this as arithmetic: the documented vested balance the borrower can actually draw, divided by the monthly distribution, compared with 36 months from the scheduled note date. When the closing date moves, the test re-runs, which is the same event logic we use for document age.
Social Security has a continuance test only for benefits paid on someone else's record. A borrower's own retirement benefit continues for life and needs no three-year showing. Survivor benefits paid to the borrower for a child are different, because a child's benefit generally stops at 18, or at 19 if the child is still a full-time student in grade 12 or below, under the Social Security Administration's rules. Fannie's Social Security Income section, B3-3.4-15, requires three years of remaining continuance for benefits like these. So the agent reads the child's date of birth from the award letter or other documentation and computes when the benefit ends. A 16-year-old's benefit on a loan closing next month has about two years left, which fails, and the agent says so with the date.
What the agent never does is estimate continuance from the borrower's own age. Regulation B, 12 CFR 1002.6(b), is direct on this. A creditor may not discount or exclude income because it is an annuity, pension or other retirement benefit, though it may consider the amount and probable continuance of any income. And age may be used only in the narrow ways 1002.6(b)(2) allows. "Probable continuance" means the terms of the benefit, documented. It does not mean a guess about how long a 74-year-old will live, and an underwriter who writes a condition asking a retiree to prove a lifetime pension will continue three years has created a fair-lending problem on paper. The agent's continuance tests are defined only on documented terms (account balances, payment schedules, a dependent's birth date), and the Rulebook entry for each test names the documentation that satisfies it. We wrote more about fair lending and AI agents separately.
What This Looks Like in the File
For each nontaxable or retirement income source, the underwriter sees the raw amount and the document it came from, the taxable and nontaxable split and the tax return lines behind it, the gross-up rate applied and the program rule that allows it, the continuance test and its result with the date it was measured against, and any reconciliation note between the award letter, the statement and the deposits. Each item is cited to a page.
Below the lender's confidence floor, or wherever the documents disagree beyond what the agent can explain, the item goes to the underwriter as a named exception. Typical ones: a benefit whose tax status changed since the last return, a pension with a survivor election the documents do not make clear, an IRA where the vested balance cannot be confirmed because the statement shows a loan against it. Triple Check runs on every figure that feeds DTI, so the nontaxable fraction is re-derived by an independent checker from the return image, not from the first extraction.
Why the Calculation Has to Be Shown
Regulation Z's ability-to-repay rule, 12 CFR 1026.43(c), requires the creditor to consider and verify the income it relies on using reasonably reliable third-party records. A grossed-up figure is a calculation on top of verified income, and the verification covers the inputs, not the result. If the input was the wrong base, the qualifying income is overstated even though every document in the file is genuine, and that is the kind of defect post-closing QC and investors find on review because it shows up in the arithmetic. The defense is a calculation that shows its inputs and the rule for each step. That is also what makes it reviewable by a person in a few seconds, which is the real test of whether an income calculation is fit for an exam.
Ramkumar Venkataraman
CTO & Co-Founder