The "Buy Borrow Die" strategy has long been a cornerstone of how ultra-wealthy families preserve and pass down wealth across generations — largely tax-free. But with margin rates now more accessible through brokers like Interactive Brokers and M1 Finance, this approach is increasingly relevant to serious retail investors as well. Here's a practical breakdown of how it works, what the risks are, and how to structure it responsibly.
What Is Buy Borrow Die?
The strategy has three phases:
Buy: Accumulate appreciating assets — typically broad index funds like VOO, VT, or SPY — over time. Avoid selling them. Every sale triggers a capital gains tax event.
Borrow: In retirement, instead of selling assets to fund living expenses, you borrow against your portfolio via a margin loan or securities-backed line of credit. Borrowed money is not taxable income. As long as your portfolio's average annual growth rate exceeds your margin interest rate, your net worth continues to compound even while you're drawing an income from it.
Die: When you pass away, your heirs inherit the portfolio with a stepped-up cost basis — meaning the original purchase price is reset to the market value at the time of inheritance. This effectively eliminates all unrealized capital gains, and your heirs can sell immediately without owing capital gains tax on decades of appreciation.
The Core Math
The strategy only works if your portfolio's growth rate exceeds your borrowing cost. Currently, competitive margin rates run around Fed Funds Rate + 1–2%, putting them near 5–5.5% for well-positioned accounts. A diversified equity portfolio has historically returned 7–10% annually. That spread — even a modest 2–4% — means your assets grow faster than your debt accumulates, allowing you to borrow indefinitely without ever needing to repay.
Compare this to the alternative: selling assets triggers a federal long-term capital gains tax of up to 20%, plus potential state taxes. For large portfolios with significant unrealized gains, paying 5% interest is almost always cheaper than paying 20%+ in taxes on liquidation.
Choosing the Right Broker for Margin Rates
Margin rates vary dramatically by broker. Most major retail brokerages charge rates that are far above competitive levels. The two most commonly recommended options for those executing this strategy seriously are:
Interactive Brokers (IBKR): Offers some of the lowest margin rates available to retail investors, often as low as Fed Funds + 0.5–1.5% for larger portfolios. Rates scale with portfolio size. You can review their current published rates at interactivebrokers.com/en/trading/margin-rates.php. Note that IBKR does issue margin calls and expects borrowers to actively manage their loan-to-value ratios.
M1 Finance: Offers margin (called "M1 Borrow") at approximately Fed Funds + 2%, which is competitive for smaller portfolios. Interface is simpler than IBKR for those less experienced with margin mechanics.
Private banking relationships can also unlock significantly lower rates. Investors willing to have a direct conversation with a private banker — particularly at institutions where they already hold assets — can sometimes negotiate rates at or near Fed Funds + 1.75% or below, regardless of what is publicly advertised.
Managing Margin Call Risk
The largest practical risk in this strategy is a margin call during a severe market downturn. If your portfolio drops sharply, your broker may require you to deposit additional funds or force the sale of assets — exactly the opposite of what you want.
Common approaches to reduce this risk:
- Keep LTV (Loan-to-Value) conservative. Most practitioners recommend borrowing no more than 20–30% of portfolio value, well below the typical maintenance margin threshold of 30–40%.
- Diversify across uncorrelated assets. A portfolio concentrated in a single sector or asset class is more vulnerable to sharp drawdowns. A mix of equity ETFs, commodity ETFs (e.g., gold), and potentially a small allocation to alternatives can reduce correlation risk.
- Maintain a cash or near-cash buffer. Holding 6–12 months of living expenses in liquid, non-margined accounts gives you the ability to pause borrowing during a downturn without being forced to sell or face a margin call.
- Consider hedging. Some investors use protective puts on their core holdings to limit downside exposure. Box spread loans are another tool — a synthetic lending mechanism executed through options that typically prices below standard margin rates and is favored by more sophisticated practitioners.
Box Spread Loans: A Brief Overview
For those comfortable with options, a box spread is a four-leg options position that synthetically creates a fixed-rate loan. The effective interest rate is typically close to the risk-free rate (Treasury yield), making it cheaper than most margin loans. Execution is more complex and requires a broker that permits multi-leg options strategies, but for large borrowing needs, the rate savings can be meaningful. This is an advanced technique and warrants thorough research before use.
Tax Considerations and Generational Wealth
The stepped-up basis at death is the lynchpin of the strategy's generational wealth angle. Under current U.S. tax law, when assets are inherited, the cost basis resets to fair market value at the date of the original holder's death. This means a portfolio purchased decades ago for a fraction of its current value can be inherited and immediately liquidated by heirs with zero capital gains tax owed on that appreciation.
Estate taxes are a separate consideration and apply above the current federal exemption threshold. For portfolios below that threshold, the combination of borrowing in life and stepped-up basis at death represents a legally sound, fully documented strategy that wealthy families have used for generations.
It is worth consulting a fee-only fiduciary financial advisor or tax attorney before implementing this strategy at scale, as individual circumstances — state tax law, estate planning documents, beneficiary designations — all affect the outcome. The IRS publishes guidance on securities-backed lending and estate planning that is publicly accessible at irs.gov.
Bottom Line
Buy Borrow Die is not a loophole or a workaround — it is a deliberate, well-documented strategy that aligns with how tax law treats borrowing versus selling. The key variables to manage are margin rate, portfolio return, loan-to-value ratio, and downside protection. Executed conservatively, with the right broker and appropriate diversification, it offers a legitimate path to tax-efficient retirement income and generational wealth transfer.
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