The $990k Apartment Dilemma: Cash vs. Mortgage

A buyer with $1.2 million in a taxable brokerage account is considering a $990,000 apartment in a hot market like New York City. The straightforward plan: sell the entire brokerage, pay capital gains taxes, and make a cash offer. But this move would wipe out a large portion of the portfolio and leave almost no liquid savings. The alternative is to take out a mortgage, keep most of the investments working, and weigh the long-term financial outcomes. This article breaks down the two paths using net present value and opportunity cost, with a focus on post-tax results and practical risk.

Key Takeaways

  • Liquidating a taxable brokerage to pay cash incurs significant capital gains taxes, potentially $150,000–$170,000, leaving minimal emergency funds.
  • Taking a mortgage preserves investment growth potential; historical stock returns often outpace real estate appreciation, leading to higher net worth over time.
  • The mortgage path provides liquidity and flexibility, reducing the risk of a forced sale during emergencies.
  • Fixed-rate mortgages become cheaper in real terms due to inflation, benefiting long-term holders.
  • The optimal choice depends on individual assumptions about investment returns, appreciation, and risk tolerance; the framework below can be adapted to personal numbers.

The True Cost of Paying Cash

Liquidating a $1.2 million taxable brokerage account with an assumed cost basis of $600,000 triggers a $600,000 long-term capital gain. Federal tax on that gain is 20%, plus the 3.8% Net Investment Income Tax, bringing the federal rate to 23.8%. New York State adds approximately 10.9% for high earners. Combined, the tax bill lands between $150,000 and $170,000. After tax, the buyer is left with roughly $1.03 million to $1.05 million. That is just enough to purchase the $990,000 apartment, leaving only $40,000 to $60,000 as an emergency fund — dangerously thin in a high-cost city where a job loss or major repair could force a distressed sale.

Beyond the upfront tax hit, a cash purchase means all equity is tied up in real estate. The buyer loses the potential for stock market gains on the entire $1.2 million. Additionally, ongoing costs such as property taxes, maintenance, and HOA fees must still be paid. In NYC, carrying costs for a $1 million apartment can range from $1,500 to $3,000 per month depending on the building and tax abatements. These costs exist regardless of whether the apartment is owned free and clear or financed.

The Mortgage Path: Leverage and Opportunity Cost

With a 20% down payment of $198,000 from the brokerage, the buyer retains about $1,002,000 invested (after paying capital gains tax only on the $198,000 withdrawn, which is much smaller). On a $792,000 jumbo loan at current rates (6.5% to 7.5% for a 30-year fixed), the monthly principal and interest payment falls between $5,000 and $5,550. Adding property taxes, insurance, and HOA, the total monthly housing cost lands in the range of $6,500 to $8,500. The mortgage interest deduction provides some tax relief, but the SALT cap of $10,000 limits state and local tax deductibility, and many filers take the standard deduction anyway, so the benefit is often modest.

The key advantage of the mortgage path is leverage. The retained $1,002,000 portfolio can grow at historical stock market returns. Using a conservative 6% to 7% annualized total return (after taxes on dividends and capital gains), the portfolio would grow to roughly $1.8 million to $2.0 million in 10 years, and $3.6 million to $4.2 million in 20 years (in nominal dollars). Meanwhile, the apartment might appreciate at a long-term average of 3% to 4% per year, reaching about $1.33 million to $1.48 million after 10 years and $1.79 million to $2.19 million after 20 years. The difference in net worth becomes substantial, especially over longer horizons.

Long-Term Net Worth Comparison

After 5 years: The cash buyer’s net worth is the apartment value (~$1.15 million at 3% annual appreciation) minus any maintenance costs, plus minimal cash savings. The mortgage buyer’s net worth includes the apartment equity (increased by loan paydown and appreciation) plus the investment portfolio. Assuming 6% investment return, the portfolio grows to about $1.34 million, and the apartment equity after 5 years (with amortization) might be around $300,000. Total net worth ~$1.64 million, significantly higher.

After 10 years: Cash buyer’s apartment worth ~$1.33 million. Mortgage buyer’s portfolio ~$1.8 million, apartment equity ~$500,000, total ~$2.3 million. The gap widens.

After 20 years: Cash buyer’s apartment worth ~$1.79 million. Mortgage buyer’s portfolio ~$3.6 million, apartment equity ~$800,000, total ~$4.4 million. The mortgage path leads to higher net worth in most scenarios, provided investment returns exceed the mortgage interest rate and real estate appreciation is moderate.

However, these projections are sensitive to assumptions. If investment returns average only 5%, the mortgage path still leads but with a smaller margin. If real estate appreciates at 2% or mortgage rates rise above 8%, the advantage shrinks. A key benefit of the mortgage path is that fixed-rate payments become cheaper in real terms as inflation erodes the debt. Over 30 years, the real cost of the loan decreases substantially.

Non-Financial Factors: Liquidity, Stability, and Legacy

Liquidity risk is a major differentiator. After paying cash, the buyer has almost no emergency fund. In a volatile job market like NYC, a layoff or medical expense could force a sale at an unfavorable time. With a mortgage, the buyer retains a large liquid portfolio that can cover several years of expenses without touching the apartment.

Psychological factors also matter. Some buyers value the peace of mind of owning debt-free, with no monthly mortgage payment. Others prefer the flexibility of having investments accessible for other goals — education, business opportunities, or early retirement. The mortgage path also allows the buyer to adjust their risk: they could sell part of the portfolio, borrow against it, or reposition into less volatile assets.

Inheritance planning introduces another consideration. Stocks receive a step-up in cost basis at death, meaning heirs can sell them without paying capital gains tax on appreciation that occurred during the owner’s lifetime. Real estate does not get a step-up in the same way — heirs inherit the property at its fair market value, but any gain from the original purchase is wiped out. This nuance favors keeping appreciated stocks, as the tax liability is erased upon death.

A Framework for Your Decision

Rather than recommending one path, here is a simplified framework that can be adapted to individual numbers. Build a spreadsheet with these inputs:

  • Apartment price and expected annual appreciation (use a range like 2%–4%)
  • Down payment percentage (20% or cash)
  • Mortgage rate (check current jumbo rates, then add 1% for sensitivity)
  • Investment portfolio value and expected after-tax return (5%–8%)
  • Capital gains tax rate (combine federal, state, Medicare surcharge)
  • Monthly carrying costs (property tax, HOA, insurance, maintenance) – estimate from listings
  • Holding period (5, 10, 20 years)

Calculate net worth at each horizon: for mortgage path, sum investment portfolio value after taxes and apartment equity (current value minus remaining loan). For cash path, use apartment value plus any remaining cash. Then adjust for taxes on investment withdrawals. The result will show which scenario yields higher net worth under the chosen assumptions.

Alternatives to consider: Instead of liquidating the entire brokerage, one could sell only enough for a 20% down payment, keeping the rest invested. Or use a margin loan against the portfolio to avoid selling entirely — but margin loans carry interest rate risk and potential margin calls if the market drops. Renting and investing the full portfolio is another option, though it forgoes ownership benefits.

FAQ

What is the opportunity cost of paying cash for an apartment? The opportunity cost is the foregone investment returns on the money used to buy the apartment. Over 30 years, the difference can be hundreds of thousands of dollars if the stock market outperforms real estate appreciation. In the example above, the mortgage path could yield more than double the net worth after 20 years.

How do capital gains taxes affect a cash offer in NYC? Liquidating a $1.2 million brokerage with a $600k cost basis incurs federal (23.8%) and NY state (~10.9%) taxes, totaling about $150k–$170k, reducing available cash to roughly $1.05 million – barely enough for a $990k apartment with minimal cushion.

Is a mortgage better than paying cash in a high-cost city? Typically, a mortgage allows an investor to keep investments working, potentially earning higher returns than the mortgage cost. However, it introduces monthly payment risk and interest costs. The better choice depends on the individual’s investment assumptions, tax situation, and need for liquidity. Running personal numbers with realistic ranges is key.