Roughly half of the mortgages in this country still carry a rate under 4%, and that is the main reason so few homes in Phoenix and Scottsdale come to market. Wolf Street's analysis of federal mortgage data counted 49.9% of outstanding loans under 4% in the first quarter of 2026, with 19.5% under 3%. Meanwhile Freddie Mac's 30-year average hit 7.28% on October 1, up from 7.03% the week before and 6.34% a year ago. A person sitting on a 3% loan is not stubborn. They are doing math.

What the lock-in effect actually is

The lock-in effect is homeowners staying in a house they might otherwise sell because their current mortgage is cheaper than any loan they could get today. It is not a feeling, it is a payment. Give up a 3% loan and take a 7.28% loan, and the same borrowing costs far more every month.

I hear it from clients in plain words. "I'd love a bigger house, but I'm not giving up my rate." They are right to hesitate. The Consumer Financial Protection Bureau's homebuying tools walk through how rate changes move the cost of a loan, and the gap here is large enough that you can see it without a calculator.

What the gap costs in dollars

On a $400,000 balance, the principal and interest payment at 7.28% is $2,737. At 3% it is $1,686. That is $1,051 a month, or about $12,600 a year, for the same amount of debt. The table shows the spread across the rate environments owners are sitting in today.

Now make it a move. Say you owe $300,000 at 3%, your payment is $1,265, and you want a $700,000 house with 20% down. That is a $560,000 loan at 7.28%, or $3,832 a month. Your housing payment goes up $2,567 before taxes and insurance, even though you only added a few hundred thousand dollars of house. That is the lock-in effect in one line.

Moving up from a 3% loan does not cost you a bigger house. It costs you the rate.

What it does to the Valley market

It keeps listings scarce, and it changes who is selling. In Metro Phoenix, the sellers coming to market are mostly people who have to move: a job, a divorce, a death in the family, or an owner who bought more recently at a higher rate and has less to lose. Owners with 3% loans who do not have to move, do not.

Wolf Street's data shows another detail worth knowing. The share of loans at 6% or higher is 22.1% nationally, the highest since 2015. More people are carrying expensive loans each quarter, which means the pool of owners who feel free to sell is growing, slowly. You can see that effect in how listings stack up. Our post on the Phoenix inventory shift covers what rising supply means for buyers.

The Homes.com Phoenix housing market report is a good place to check current supply and days on market against what you have heard. And the Federal Housing Finance Agency publishes a house price index that shows how long prices have held up even with few sales. Low supply is part of that story.

Four things a locked-in owner can do

You have more choices than selling or sitting still. Here is how I walk clients through it.

• Stay and improve. If the house works, spend on the house. A $40,000 remodel is cheaper than $2,567 a month more in payment.
• Rent it out and buy again. You keep the 3% loan, you collect rent, and you finance the next home on its own terms. This only works if the rent covers the payment, taxes, insurance, and a vacancy cushion. Our guide on renting out or selling your Arizona home has the numbers.
• Borrow against equity instead. If you need cash and not a different house, a second lien can leave the first mortgage alone. See HELOC versus a bridge loan. The tradeoff is that the second loan usually costs more.
• Sell with a buydown on the next purchase. A seller concession or builder credit can cut the early payments on the new loan. Read how seller-paid rate buydowns work before you count on one.

Run your own numbers

What about assuming someone else's low rate?

An assumable loan is the one real way to buy a house and keep the seller's rate. FHA and VA loans can generally be assumed by a qualified buyer, and the Department of Veterans Affairs home loan page explains how VA assumptions work. Conventional loans generally cannot be assumed.

The catch is the gap. If a seller owes $300,000 on a $650,000 house, the buyer has to bring the $350,000 difference in cash or a second loan. That second loan is priced at today's rates, so the blended rate is higher than the 3% headline. Our breakdown of assumable mortgages in Arizona shows how the blend works in practice.

Why the lock-in is getting stronger, not weaker

The Fed has been raising rates, and Forbes reported on September 29 that markets are pricing in hikes at both remaining meetings this year, October 28 and December 9. Mortgage rates are not the Fed's rate, but they move in the same direction when inflation stays high. Every time rates go up, the 3% loan gets more valuable to its owner and the incentive to move gets smaller.

If you are a buyer, this is useful to know. A seller who has to move cannot wait out the market, and a seller who does not have to move will not budge on price. Figure out which one you are dealing with before you write an offer. When a listing has sat for 40 days, there is usually a reason, and sometimes the reason is a seller with a deadline. You can browse current Scottsdale and Phoenix listings on the Arizona Luxury Property Search.

What this means for Scottsdale and Valley buyers

Expect fewer choices, firmer sellers, and a payment that rewards the buyer who plans. Get pre-approved on today's rate, not last year's, so you know your real number. Look at the structure of the deal, not just the price: a seller credit that buys down your rate for two years can be worth more than a $10,000 price cut. Our loan programs page lists the options we shop, and how our process works shows what pre-approval looks like from the first call. If you want to know who is running your file, here is more about Pillar Mortgage Group.

Want your own numbers on a move? Start at pillarmortgagegroup.com, book a call, or fill in the form below. I will run it with you.

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