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Backup Contracts · 10 min read · Updated April 2026 · By Mike Certo

The $2,500 Guaranteed Backup Contract: A Complete Walk-Through

If your debt-to-income ratio breaks the moment a second mortgage payment shows up on paper, the Guaranteed Backup Contract is the cleanest, cheapest way out. This is the full walk-through, including the actual pricing tiers, what triggers the backup, and what stays in your control.

The DTI problem, in one paragraph

Mortgage underwriting works off your debt-to-income ratio (DTI): your monthly debts divided by your monthly gross income. When you’re trying to buy a second home before selling your first, the underwriter has to count both housing payments, your current PITIA (principal, interest, taxes, insurance, and any HOA dues) plus the new home’s. For most move-up buyers, that combined number is too high, and the loan is denied or the buyer is forced into a sale-of-home contingency that sellers won’t accept in a competitive Arizona market.

What the Guaranteed Backup Contract is

A Guaranteed Backup Contract (GBC) is a written, non-contingent offer from a vetted institutional buyer (Fly Homes) to purchase your current Arizona home at a guaranteed price. Because that offer exists, multiple loan programs allow your underwriter to exclude the current home’s PITIA from the DTI calculation, your current housing payment effectively disappears from qualifying math.

The GBC is a financing tool, not a sale. You still list your home with the agent of your choice. You still negotiate. You still keep upside above the backup price if you sell on the open market.

How it works, step by step

  1. Submit the home. We send the property to Fly Homes for an internal valuation.
  2. Backup offer issued. You receive a non-contingent written offer from the backup buyer, issued against fair-market value of your current home. The program includes an equity pledge that protects homeowners, ask about it in the consult.
  3. DTI is fixed. The new mortgage underwriter excludes the current PITIA from your DTI ratio.
  4. You buy the new home. Clean offer, no sale-of-home contingency, normal close.
  5. You list and sell normally. Your agent, your price strategy, your timeline within the 180-day window.
  6. Backup either cancels or triggers. Sell on the open market in 180 days → backup contract is canceled. Don’t sell → backup buyer purchases at the guaranteed price.

Pricing tiers — what it actually costs

Pricing is tiered by the guaranteed offer price (not by your home’s sale price).

Guaranteed price up to Fee
$500,000$2,500
$750,000$3,500
$1,000,000$5,000
$1,500,000$7,500
$2,000,000$10,000
> $2,000,000Reviewed on exception

You can request a lower offer price to reduce cost. The offer only needs to exceed the outstanding lines on the property, including the HELOC limit, regardless of how much you’ve drawn. Smaller backup offer = lower fee.

Apples-to-apples comparison. National Buy Before You Sell competitors typically charge 2.4% of the sale price plus closing costs. On a $750,000 Scottsdale sale, that’s roughly $18,000. Same outcome, very different bill. The Cornerstone GBC is a flat-tier program, savings of $10,000–$15,000+ are normal at mid-market price points.

Loan programs that qualify

Programs that play well with the GBC:

  • Conventional: eligible.
  • VA: eligible.
  • Jumbo & Non-QM: eligible.
  • FHA: not allowed.

What stays in your control

  • Your listing agent. Your choice. The backup contract is financing, not a referral or commission grab.
  • Your list price and strategy. You and your agent decide.
  • All open-market upside. If you sell for more than the backup price, you keep every dollar above it.
  • Your timeline within 180 days.

The 180-day window

You have 180 days from the contract’s effective date to sell on the open market. Most Arizona homes sell well within that window. If yours doesn’t, Fly Homes purchases at the guaranteed price, makes any necessary repairs and upgrades, and resells the property. Net sale proceeds above the transaction and repair costs are returned to the seller.

Be honest with yourself in the consult: if you have real reason to believe the home will take longer than 180 days to sell (an unusual property, a difficult micro-market, deferred maintenance), the GBC may not be the right fit, and we’ll say so.

Pairing with a bridge loan

If your roadblock is both DTI and down-payment cash, you stack. The bridge loan hands you the cash; the GBC fixes the DTI. Two tools, one underwriting file, one close.

When it’s not the right fit

  • Your loan program is FHA, not eligible.
  • You have real concerns the home won’t sell in 180 days.
  • The property’s outstanding lines (mortgage + full HELOC limit) exceed what the backup offer can be.
  • DTI isn’t actually your roadblock, you might just need a bridge loan.
If a Buy Before You Sell program isn’t the right answer for your situation, we’ll tell you in the consult and walk you through what is.

Next step

If you’re carrying a current mortgage and shopping for the next home in Phoenix, Scottsdale, Mesa, Tempe, Chandler, Gilbert, Glendale, or Tucson, and you’ve been told your DTI is too high, this is the conversation to have. Start your application with us so we can pre-approve you and model the backup-contract tier in the same file.

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