- 0137 million homeowners have sub-4% mortgages — they're not selling, creating an artificial supply shortage
- 02New listing inventory is down 35% from 2019 levels in most metros — that's the lock-in effect
- 03Affordability index is at its worst since 1985 — a $300K home costs $600/month more than in 2021
- 04Investors filling the gap with rentals: buy-and-hold demand in secondary markets is up 22% YoY
Show Notes
The Lock-In Effect
37 million homeowners are sitting on mortgages below 4%. Trading a 3.2% rate for 7% on a new house would add $800 a month to the payment. So they stay put — and supply collapses. New listing inventory is down 35% from 2019 levels in most metros. Phoenix, Atlanta, Dallas — same story. Redfin's Q2 2025 data shows new listings down 34% in Seattle, 38% in San Diego, 41% in Boston. This isn't a blip. It's structural, and it'll last until rates drop significantly or life events — divorce, relocation, death — force sellers' hands.
Affordability Math
A $300,000 home at 3% in 2021 ran about $1,265/month in principal and interest. Same home at 7% today: $1,996. That's $731 more per month. The National Association of Realtors affordability index is at its worst since 1985. Median household income is up about 15% since 2020, but housing costs have jumped 50% in that same window. Cash buyers and investors are the ones still closing. Renters who can't afford to buy stay put — which keeps rental demand strong.
Rental Tailwind
If people can't buy, they rent. Vacancy rates sit at 5.8% nationally as of mid-2025, down from 6.5% in 2020. In secondary markets — Memphis, Indianapolis, Birmingham — cash-flow deals still exist. Cap rates have compressed in the hottest metros, but you can still find 6–7% in the right neighborhoods. A $150K duplex in Cleveland grossing $2,200/month hits a 7.5% cap rate before expenses. The lock-in effect is a tailwind for landlords: renters who would have bought in 2021 are still renting in 2025.
Where the Deals Are
Buy-and-hold demand in secondary markets is up 22% year over year. A $180K duplex in Columbus renting for $1,400 a side is a different conversation than a $600K duplex in Denver. House hacking works best when purchase prices are lower — FHA at 3.5% down on a $200K triplex in Kansas City puts your out-of-pocket at $7,000, with the other units covering most of the payment. The shockwave has pushed opportunity inland. Rates might drift to 6% or 6.5%, but those 37 million people aren't selling tomorrow. Find the markets where cap-rate and cash-flow math still works — that's your edge.
Resources Mentioned
- Financing Your Investment Property — loan types, qualification, and strategy for today's rate environment
- Deal Analysis Guide — the metrics framework for cap rate, cash flow, and vacancy analysis
- BRRRR Refinance Timing — when to refinance and how hold periods affect your numbers
- Rental Property Calculator — run your own cap rate and cash flow analysis with real numbers
- Freddie Mac Mortgage Rate Survey — weekly 30-year and 15-year fixed rate averages
The ratio of a loan amount to a property's appraised value, expressed as a percentage — a 75% LTV on a $200,000 property means a $150,000 loan and $50,000 in equity.
Read definition →Cap rate measures a property's annual net operating income as a percentage of its purchase price or current market value, assuming an all-cash purchase.
Read definition →Cash flow is what's left in your pocket after a rental pays all its expenses — including the mortgage. NOI minus debt service. What actually hits your bank account each month or year.
Read definition →The percentage of time a rental property sits empty and produces no income, calculated as vacant units divided by total units — the silent profit killer in rental investing.
Read definition →House hacking is living in one unit of a multi-unit property (or renting rooms in a single-family) while tenants pay most or all of your mortgage — turning your housing cost into an investment.
Read definition →
