Avoid any big purchase before closing on a house. Financing a car, opening a store credit card, draining savings on furniture, or even co-signing someone else’s loan can push your numbers past the limits that got you approved. Lenders verify your debt, income, and credit right up to the moment your loan funds, and a single new obligation is enough to delay closing or sink the deal.
What Counts as a Big Purchase
“Big” is relative to your financial picture, not the sticker price. A $400 car payment barely registers for a high earner but can disqualify a first-time buyer who was already close to the debt limit. The purchases that cause the most trouble fall into two groups: financed purchases that add a monthly obligation, and large cash outlays that drain the reserves your lender is counting on.
Financed purchases are the bigger threat. A car loan, a furniture store credit account, appliances financed through a retailer — any of these adds a monthly payment the underwriter has to count against you. Even opening a new credit card with a zero balance matters, because the lender treats it as a new potential obligation and the application generates a hard inquiry on your credit report.
Cash purchases cause a different problem. If you spend a chunk of savings on a riding mower, a home gym, or moving costs, you can fall below the reserve requirements your loan program demands. Fannie Mae requires no minimum reserves for a standard single-family primary residence, but individual lenders routinely add their own thresholds on top of program minimums.1Fannie Mae. Minimum Reserve Requirements Spending the money you earmarked for closing costs or a post-closing cushion can violate those requirements even when the purchase itself seems modest.
Co-signing Counts Too
Co-signing a loan for a friend or family member has the same effect on your mortgage application as taking the loan out yourself. Lenders count the full monthly payment of any co-signed debt against your income regardless of who actually pays it. A co-signed $420 auto lease on $4,000 of monthly income jumps your debt ratio by more than 10 percentage points in one stroke.
The only way to exclude a co-signed debt is to prove the primary borrower has made 12 consecutive months of payments entirely from their own account, documented with bank statements or canceled checks. If you co-signed your child’s student loan six months ago, the lender will almost certainly count that payment against you. Doing a favor during the mortgage process is one of the most expensive mistakes a borrower can make.
How New Debt Breaks Your Debt-to-Income Ratio
Your debt-to-income ratio is the single most important number in mortgage underwriting. It divides your total monthly debt payments by your gross monthly income.2Consumer Financial Protection Bureau. What Is a Debt-to-Income Ratio Lower is better, and the trouble is that most borrowers are approved near their ceiling, with almost no margin for new debt.
The limits vary. For conventional loans sold to Fannie Mae, the maximum is 36% for manually underwritten loans, stretching to 45% with strong credit and sufficient reserves. Loans run through Fannie Mae’s automated underwriting system can go as high as 50%.3Fannie Mae. Debt-to-Income Ratios FHA loans allow up to 43% as a baseline, with compensating factors pushing the ceiling to 50% in some cases.
The math is unforgiving. If you earn $6,000 per month and your current debts total $2,700, your DTI is already 45%. Add a $350 car payment and you’re at nearly 51%, past every conventional limit. Lenders don’t round down or make exceptions because you’re close. These thresholds are tied to secondary market requirements, and even a $50 monthly payment can be the difference between approval and denial.
Credit Score Damage
New debt hits your credit score from two directions at once. First, applying for financing triggers a hard inquiry. A single hard inquiry typically costs fewer than five points on a FICO score, and that impact lingers for up to a year.4Experian. What Is a Hard Inquiry and How Does It Affect Credit That sounds small, but mortgage pricing tiers sit at round numbers like 680, 700, and 720. A three-point drop at the wrong moment can bump you into a worse pricing tier or disqualify you from your loan program entirely.
The second hit comes from credit utilization, which measures how much of your available credit you’re using. This factor accounts for roughly 30% of your FICO score.5myFICO. How Are FICO Scores Calculated Charging $3,000 on a card with a $5,000 limit spikes utilization to 60%, which can shave 20 or more points off your score. If that pushes you below the minimum score your loan requires, the lender may need to restructure the loan at a higher rate, require private mortgage insurance you didn’t budget for, or deny the application outright.
Multiple hard inquiries in a short period send a signal underwriters don’t like. One pull from a car dealer and another from a furniture store in the same week looks like financial scrambling, and it is enough to raise concerns during final review.
Large Deposits Are Also a Problem
Spending isn’t the only side of the ledger that triggers scrutiny. Receiving money does too. Fannie Mae defines a large deposit as any single deposit exceeding 50% of your total monthly qualifying income.6Fannie Mae. Depository Accounts If you earn $4,000 per month and deposit $2,500, the lender has to document where that money came from before counting it toward your down payment, closing costs, or reserves.
This catches borrowers who sell personal property, receive gifts from family, or consolidate accounts right before closing. The fix isn’t complicated but it takes time: you’ll need a paper trail showing the deposit came from an acceptable source. For gift money, Fannie Mae allows contributions from relatives, domestic partners, and people with a long-standing family-like relationship, but not from anyone with a financial interest in the deal.7Fannie Mae. Personal Gifts If you plan to receive gift money or move funds between accounts, do it early and tell your loan officer before they see it on a statement.
Job Changes During the Mortgage Process
Employment stability matters as much as debt levels. Fannie Mae requires lenders to verify your employment within 10 business days before closing.8Fannie Mae. Selling Guide Announcement SEL-2024-02 If your employer tells the lender you resigned last week, the loan stops.
Switching jobs doesn’t automatically kill your approval, but some changes are far more disruptive than others. Moving from one salaried position to a similar salaried position in the same industry is usually manageable. Switching from a W-2 salary to commission-based pay, freelance work, or 1099 contractor status is different. Lenders view variable income as higher risk and may require two full years of self-employment tax returns before counting that income toward qualification. If a job change is unavoidable, tell your loan officer immediately so they can assess the impact before the underwriter discovers it on their own.
The Pre-Closing Credit Refresh
Lenders don’t just trust that nothing changed since your application. A few days before closing, most lenders pull a refresh credit report to check for new debts, new inquiries, or changes to existing accounts. Many investors now require this check, or an undisclosed debt monitoring service, at least 10 days before closing to leave time for resolution.
The lender compares the updated report against your original application. If new accounts, balances, or inquiries appear, closing pauses while the underwriter recalculates your ratios and verifies you still qualify. You’ll need to provide a written explanation for any new inquiry, and the lender may order a supplemental credit report to get full details. This process adds days to your timeline and can result in denial if the new debt pushes your DTI or credit score past qualifying limits.
This is where borrowers who made a “small” purchase during underwriting get caught. That store credit card you opened for 10% off a washer and dryer shows up on the refresh, and you’re explaining it to an underwriter three days before you were supposed to get your keys.
The Real Cost of a Delayed Closing
When a big purchase triggers a re-review and pushes closing back, the financial consequences go beyond inconvenience. If your interest rate lock expires while the lender sorts out the problem, you’ll likely need to pay for an extension. Most lenders offer extensions in 15-day increments, typically costing between 0.125% and 0.25% of the loan amount. On a $400,000 loan, that’s $500 to $1,000 per extension just to hold your rate.
Your purchase contract may also include a per diem penalty for closing after the agreed-upon date, compensating the seller for the delay. A delayed closing can strain the entire chain of transactions if the seller is simultaneously buying another home, which can expose you to liability for their losses as well.
When You Can Safely Spend Again
Signing the closing documents is not the finish line. Your loan is only complete once the lender reviews the signed package, wires the funds, and the deed is officially recorded with your local government office. The gap between signing and recording can run from a few hours to several business days, depending on your state and the type of closing. During that window, the lender still has the right to pull credit or verify employment one final time.
The only safe rule is to wait until the deed is recorded and you have confirmed with your loan officer or title company that funding is complete. Once the money has changed hands and the county has recorded the transfer, your lender has no further ability to alter the terms or rescind the loan based on new purchases. That’s the moment to order the furniture, finance the appliances, or start shopping for everything the new home needs.
What to Do If You Already Made a Big Purchase
Call your loan officer immediately. Hiding the purchase makes things worse, because the pre-closing credit refresh will reveal it anyway, and an underwriter who discovers undisclosed debt treats it as a much bigger red flag than one you reported voluntarily.
Your loan officer can run the numbers before the underwriter sees the change and tell you where you stand. Sometimes the new debt still leaves you within qualifying limits and the impact is minor beyond extra documentation. If the purchase pushed you over a threshold, your options depend on the specifics: paying off the new balance in full before the credit refresh, returning a financed item and having the account closed, or bringing additional funds to closing to offset depleted reserves. None of these fixes is guaranteed to work, and all of them add time and stress to a process already on a deadline. The cheaper approach is to wait a few more days and buy everything after recording.