The Lock-In Effect: Why North Shore Inventory Is So Tight Right Now
There’s a question I get more than almost any other right now, and it comes in several forms. From buyers: why is there nothing out there? From sellers considering a move: why does it feel like nobody else is listing? From neighbors who’ve been watching the same two houses sit on the market while the rest of the street stays quiet: what’s going on?
The honest answer is a single phenomenon that economists have been tracking since mortgage rates spiked in 2022 — and that is still reshaping the housing market in 2026. It’s called the lock-in effect. Understanding it won’t make inventory materialize overnight, but it will help you read the market for what it actually is rather than what you might hope it to be.
The Math Behind the Silence
Here’s the core of it. During the pandemic years, mortgage rates hit historic lows — rates below 3% weren’t rare, they were common. Millions of homeowners refinanced or purchased at those levels. As of mid-2025, more than 80% of U.S. mortgage holders still carry rates below 6%. And a substantial portion of that group — roughly half of all mortgaged homeowners, per Redfin’s analysis of Federal Housing Finance Agency data — hold rates at or below 4%.
Now consider what it means to give one of those rates up.
A homeowner carrying a $500,000 mortgage at 3% pays roughly $2,108 per month in principal and interest. At today’s prevailing rates — hovering in the 6% to 6.5% range — that same balance costs approximately $3,160 per month. That’s an increase of more than $1,000 per month, or more than $12,000 per year, in mortgage costs alone. Before taxes. Before insurance. Before anything else.
For a household that bought or refinanced between 2020 and 2022, the financial logic of staying put is nearly airtight. They are not being irrational. They are doing the math and the math is telling them to stay.
What This Means for the North Shore
The North Shore has always had constrained inventory relative to demand. We are not a tract-home market. The communities along the Sound — Mount Sinai, Sound Beach, Miller Place, Port Jefferson, Setauket, Stony Brook, St. James — are largely built out, with distinctive properties that don’t come to market frequently under any conditions.
Layer the lock-in effect on top of that structural tightness, and you get what buyers are experiencing right now: a market where well-priced homes move quickly and the “options” feel thin.
This isn’t a local anomaly. National housing economists have been consistent in their read: the lock-in effect has reduced home sales significantly from where they would otherwise be, and while it’s slowly loosening — as more owners hold rates above 6% and life events force decisions regardless of rate conditions — it is not going away this spring. Realtor.com chief economist Danielle Hale has noted that the challenges of the lock-in effect will persist through 2026, even as its grip gradually weakens.
Who Is Still Listing?
The owners coming to market right now tend to fall into recognizable categories: retirement and right-sizing, estates and inherited properties (which carry no rate anchor), job-driven relocations, divorce, health changes. The full catalog of life events that don’t wait for the Fed to act.
What you are not seeing — not yet, in meaningful numbers — is the discretionary seller. The household that has been thinking about upsizing or moving to a different neighborhood but has no hard timeline. That household is largely still waiting. The rate math has to shift more meaningfully before the calculus changes for them.
What Buyers Should Take From This
Competition on quality properties remains real. When something comes to market that is well-priced, well-located, and well-presented, buyers on the North Shore are still encountering multiple offers and compressed timelines. The “looser” market that national headlines sometimes suggest is not evenly distributed — it is more pronounced in markets with oversupply, particularly parts of the Sun Belt and the South Shore. The North Shore’s structural inventory constraints mean that even a modest thawing of the lock-in effect will not produce a flood of listings here.
Buyers who wait for a wave of inventory may be waiting longer than they expect. Buyers who position themselves to move quickly — pre-approved, clear on their criteria, working with a broker who knows which properties are coming before they hit the MLS — are the ones finding the homes.
What Sellers Should Take From This
If you are one of the homeowners sitting on a low rate and wondering whether this is your moment to move, the honest answer is: it depends entirely on your reasons and your math.
If you are selling to downsize significantly, the rate differential hurts less than it looks, because you are borrowing less. If you are selling to move laterally or upsize, the monthly payment increase is real and you should model it carefully before you commit. If your reasons for moving are life-driven rather than purely financial, the rate is a cost of doing what you need to do — not a reason to postpone indefinitely.
The most credible forecasts for 2026 put 30-year rates in the 6% to 6.4% range — modest improvement from recent peaks, but not a return to the pandemic-era lows that created this situation. If a move makes sense for your life, the conversation is worth having. That’s what I’m here for.
Real estate markets change. This post reflects conditions as of April 2, 2026. For current listings and market data, contact Pawli at Maison Pawli.
Sources
Redfin Analysis, FHFA National Mortgage Database, Q2 2025
Realtor.com / Danielle Hale, via Axios, January 2026
NAR 2026 Real Estate Outlook
2026 US Housing Market Forecast (Realtor.com data)
