Home Loans vs. Buying Outright for High-Net-Worth Buyers

For most people, the goal is to pay off their mortgage as fast as possible. Debt is a burden, interest is waste, and owning your home free and clear is a milestone worth celebrating. This is sensible financial advice for most households.

For high-net-worth individuals — including lottery winners with significant liquid assets — the calculus is often different. In certain rate environments, taking a mortgage and keeping the rest invested is not just defensible; it is demonstrably the wealthier outcome. In other environments, paying cash is clearly better.

The answer depends on three things: the interest rate on the mortgage, the expected return on your investments, and whether you have the financial discipline to actually invest the difference rather than spend it.

The core concept: leverage and opportunity cost

When you pay cash for a home, you convert liquid, investable capital into an illiquid asset. The home may appreciate, but it does so at a rate entirely unrelated to what your portfolio could have earned. You have also eliminated the debt — but at the cost of opportunity.

The opportunity cost of paying cash is whatever you would have earned by keeping that money invested. If a $2 million home could instead be financed with a mortgage at 6%, and you can earn 8% on a diversified portfolio, then every dollar you used to buy the house outright is costing you the 2% spread — compounded over decades.

This is sometimes called “leverage” in investing contexts, though it is simpler here: you are borrowing at 6% and investing at 8%. If the math works in your favor, it makes sense to borrow. If it doesn't — if the mortgage rate equals or exceeds your realistic investment return — paying cash is the rational choice.

The numbers: when does the mortgage win?

Consider a buyer who has $2 million in cash and is purchasing a $2 million home. They can pay in full or put 20% down ($400,000) and take a mortgage for $1.6 million. Both paths end at the same place — a home they own outright — but through very different routes.

Path A: Pay cash. They spend $2 million. No mortgage payment. Going forward, they invest whatever they would have paid monthly — say $10,644 per month (the equivalent P&I payment on a $1.6M, 7% 30-year mortgage) — into a diversified portfolio.

Path B: Take the mortgage. They put $400,000 down and invest the remaining $1.6 million immediately in that same portfolio. They pay $10,644 per month to the lender instead of investing it.

After 30 years, at a 7% investment return:

• Path A (pay cash, invest monthly): approximately $12.8 million in investments
• Path B (mortgage at 7%, invest lump sum): $1.6M grows to ~$12.2M, minus ~$2.2M in total interest paid = approximately $10.0 million

At 7% borrowing rate and 7% returns, paying cash wins. The monthly compounding of Path A beats the lump sum growth of Path B once you account for the interest cost.

But change the interest rate to 3% — as many homeowners experienced during 2020 and 2021 — and the picture reverses dramatically:

• Path A (pay cash, invest monthly $6,745/mo at 7%): approximately $8.1 million
• Path B (mortgage at 3%, invest $1.6M at 7%): $1.6M grows to ~$12.2M, minus ~$830k in interest = approximately $11.4 million

At a 3% mortgage rate and 7% returns, the mortgage path leads by approximately $3.3 million over 30 years. This is why wealthy investors who refinanced or purchased at pandemic-era rates were so reluctant to pay off their mortgages — the math simply did not support it.

You can model your own numbers with our mortgage calculator, which includes an opportunity-cost comparison at any assumed investment return.

The tax dimension

The comparison above is pre-tax. Taxes affect both sides.

Mortgage interest deduction. Federal tax law allows homeowners to deduct mortgage interest on up to $750,000 of mortgage debt (for loans originated after December 2017). For a $1.6 million mortgage, only the interest attributable to the first $750,000 is deductible. At a 7% rate, that's roughly $52,500 of deductible interest in year one — worth about $19,000 in tax savings for someone in the 37% bracket.

As the mortgage balance falls below $750,000, the full interest becomes deductible. For very large mortgages, the benefit is real but limited, and many high-income taxpayers are subject to the alternative minimum tax, which further restricts itemized deductions.

Investment tax drag. Returns on taxable investment accounts are not free — dividends are taxed annually, and gains are taxed on realization at capital gains rates (0%, 15%, or 20% for most). A nominal 8% portfolio return might produce a 6–7% after-tax return once you account for dividend taxes and periodic rebalancing.

This tax drag narrows the spread between your investment return and your mortgage rate, which favors paying cash more than a pre-tax comparison suggests. The precise effect depends heavily on your portfolio composition and tax situation. Your tax advisor can model this accurately for your specific circumstances.

Liquidity and flexibility

There is a non-financial argument for taking the mortgage that is often underappreciated: liquidity. A home is one of the most illiquid assets in existence. Converting cash into a home means that cash is no longer available for other uses — emergencies, investments, charitable giving, business opportunities, or anything else.

High-net-worth individuals who pay cash for expensive real estate often find that a significant portion of their net worth becomes concentrated in a single illiquid asset. This is a form of concentration risk. If the local real estate market declines, or if you need to sell quickly for any reason, a cash-heavy home purchase has limited your flexibility.

A mortgage preserves that liquidity. Your invested assets remain accessible (with some tax implications for redemption, but accessible nonetheless). Your home equity builds over time, but you retain a diversified portfolio rather than a concentrated real estate position.

For lottery winners in particular, who are often building a financial portfolio from scratch, liquidity matters. Tying up a significant portion of your windfall in a single property limits your ability to respond to investment opportunities, family needs, or life changes in the years immediately after winning.

What wealthy people actually do

The behavior of ultra-high-net-worth individuals and their advisors provides a useful data point. During the low-rate environment of 2012–2022, financial advisors to wealthy clients almost universally recommended taking or keeping mortgages rather than paying them off. The reasoning was straightforward: borrowing at 3% and earning 7–8% in a diversified portfolio was a near-certain positive carry.

Many of the wealthiest Americans carry significant mortgage debt by deliberate choice — not because they need the money, but because the math supports it. Warren Buffett has discussed this publicly, noting that his 30-year fixed-rate mortgage on his Omaha home was one of the best investments he ever made precisely because he kept the capital working elsewhere.

In the higher-rate environment of 2024–2026, the calculus is less clear-cut. With 30-year fixed rates in the 6–8% range, the spread between mortgage cost and realistic investment returns has narrowed significantly. At 7% borrowing and 7–8% expected returns, the financial case for a mortgage is marginal, and the emotional case for owning outright becomes more competitive.

The discipline requirement

The entire argument for taking a mortgage rests on a critical assumption: that you actually invest the money you don't spend on the house, and keep it invested. If you take a mortgage and spend the proceeds — or let the cash sit in a low-yield account — you get all the downside of debt with none of the upside of compounding returns.

This is where many people fail in practice, and it's why some advisors still recommend paying cash even when the math favors a mortgage. The math is correct on paper. Human behavior in practice often isn't.

For lottery winners in the first year after winning — when social pressures are intense, when family is asking for money, when the temptation to upgrade every aspect of life is constant — keeping a large portfolio invested and untouched requires discipline that is genuinely difficult to maintain. If you have any doubt about your ability to leave the invested capital alone, paying cash for the home eliminates the risk of the strategy unraveling.

The psychological case for paying cash

There is a real and underrated argument for simply paying cash: peace of mind. The knowledge that you own your home outright — that no lender has a claim on it, that no market disruption can threaten your housing — has genuine value that doesn't appear in any financial model.

Some people sleep better without debt. Some people find that the absence of a monthly payment changes their relationship to their work and financial decisions in positive ways. Some people genuinely don't want the complexity of managing a portfolio large enough to justify the mortgage carry.

These are legitimate considerations. Personal finance is personal. If the financial advantage of a mortgage is $500,000 over 30 years but it costs you years of stress and complexity, the trade-off may not be worth it. Advisors who are honest about this tend to be better advisors.

A framework for deciding

The right answer depends on your specific situation. A few questions that clarify it:

1. What is the current mortgage rate? At rates below 5%, taking a mortgage is almost always the financially superior choice for a disciplined investor. At 7%+, it is much closer to break even, and the decision depends heavily on your assumed return.
2. What return can you realistically expect? A fee-only financial advisor can help you model realistic returns for a portfolio matched to your risk tolerance. Don't use 10% as your assumption unless you're comfortable with a highly equity-heavy portfolio and a long time horizon.
3. Will you actually keep the money invested? Be honest about this. If there's a meaningful chance the money gets spent over time, paying cash is better.
4. How much of your net worth would the home represent? If paying cash for a home would represent more than 20–30% of your total net worth, liquidity risk becomes a serious concern, and a mortgage is likely the right call regardless of the rate comparison.
5. What does your tax situation look like? The mortgage interest deduction and the tax drag on investments affect the comparison in ways that vary significantly by individual. Run the after-tax numbers with a CPA.

Our mortgage calculator lets you model the opportunity-cost comparison at any interest rate and assumed investment return. Use it as a starting point for the conversation with your financial advisor.