Bitcoin-Backed Mortgages

The structural argument on Borrowing Against Your Stack applies in full here: if you believe bitcoin’s long-run trajectory continues to produce a compound annual growth rate meaningfully higher than your cost of debt, every coin sold today is a coin that compounds for someone else, instead of for you. For the housing transaction specifically, the case to borrow against bitcoin rather than sell has held up for years but has been practically blocked by the lack of a regulated product. The Fannie-Mae-conforming offering closes that gap. That regulators landed on bitcoin specifically, rather than “crypto” broadly, is itself a meaningful signal about where the regulated tier has come down on collateral quality.

When this makes sense — and when it doesn’t

This page isn’t recommending bitcoin-backed mortgages. Like the parent Borrowing Against Your Stack page, the editorial mission is structural literacy: walk you through what the product is, how it’s different from its CeFi predecessors, what risks remain, and what the trade-off actually is — so you can evaluate it on your own terms.

A note on eligibility worth flagging upfront: the Fannie Mae-conforming product is available for primary residences, second homes, vacation homes, investment properties, and most multi-unit configurations that meet conventional Fannie Mae criteria. The product is not restricted to owner-occupied housing the way some older crypto-collateral offerings were. For purposes of the trade-off discussion below, the question is whether this specific financing structure fits your situation — not whether you’re allowed to use it for the property type you have in mind.

The trade clears the bar when several conditions are met together:

• You have the income to service the monthly mortgage payments from your day-job cash flow. The “no margin call” feature only protects you against price volatility; it doesn’t protect you against income loss.
• You’re prepared to lock up roughly 2.5× the down-payment amount in pledged bitcoin for the life of the loan — or you’re satisfied that you can pursue an early repayment of the second-lien (or the full mortgage) at a later date, when bitcoin has appreciated enough to make that preferable.
• You’re comfortable holding that bitcoin at Coinbase Prime custody for the duration. Self-custody and hardware-wallet storage are not currently accepted by the product.
• Your remaining bitcoin stack (the portion not pledged) is large enough that the pledged collateral represents a modest fraction of your total exposure to bitcoin — a Day-60 default scenario doesn’t risk forcing liquidation of the bulk of your position.
• You’d rather not crystallize the capital-gains liability on the pledged BTC at this stage of your life. The tax deferral compounds across decades, especially for younger holders.
• You believe bitcoin’s long-run trajectory continues to produce a compound annual growth rate meaningfully higher than the mortgage rate over the duration of the loan. This is the Power Law channel argument; it has to be true for the pledge to be the better path.

The trade fails the bar when:

• You expect frequent active management of, or short-term reallocation across, the pledged portion of your stack. The product can be unwound early (refinance, retire the lien from cash flow, or sell the home), but each unwind is a deliberate transaction rather than a routine reallocation — if you’d want to move the pledged BTC weekly or monthly rather than make a single decision over a multi-year horizon, this isn’t the right vehicle.
• Self-custody is a hard requirement for you. The product mandates Coinbase Prime custody for the life of the loan; if moving the pledged portion to a regulated custodian is a non-starter, this product isn’t available to you in its current form.
• The mortgage payments stretch your monthly cash flow such that any income disruption puts the entire structure at risk — the no-margin-call feature protects against bitcoin’s price moves, not against your salary going away.
• You don’t actually believe in the long-duration bitcoin appreciation case — in which case selling some BTC for the down-payment is genuinely the cheaper path, since you’re not giving up appreciation you don’t expect to see.
• You’d be relying on the mortgage-interest tax deduction to make the economics work — the deduction is real but smaller than marketed, and the standard-deduction comparison usually narrows it materially.

Anatomy of the product

The transaction is a two-loan structure, not a single bitcoin-backed mortgage. The primary mortgage is a 30-year conforming loan against the property — fully Fannie-Mae-conforming, fully securitizable, with the standard servicing infrastructure that implies. Riding alongside it is a second-lien down-payment loan collateralized by pledged bitcoin (or USDC) held with a regulated custodian. The pair operates together: the second-lien funds the down payment so the borrower doesn’t have to sell BTC; the primary mortgage covers the rest in the conventional way. Better and Coinbase describe one structural feature as a market first: both loans share a single interest rate and amortization term, so the borrower manages one combined monthly payment rather than two separate ones. The combined rate runs roughly 0.5 to 1.5 percentage points above a standard 30-year, depending on the borrower profile — that premium applies to the full borrowed amount, not only to the second-lien.

The second-lien is a normal amortizing loan, not a balloon facility. As long as you make the monthly payments, your bitcoin sits in custody untouched for the full life of the loan.

The life of the loan is your decision to make. Federal Qualified-Mortgage rules sharply restrict prepayment penalties on conventional mortgages — any allowed penalty is capped at 2% of the outstanding balance in the first three years and zero thereafter — and Better’s product explicitly returns pledged bitcoin in full after the loans are fully repaid, refinanced, or paid off via home sale. If bitcoin appreciates substantially during the loan term and you want to retire the second-lien (or the whole structure) to free the collateral for other purposes, that path is open. The 30-year duration is a ceiling on how long the structure can run, not a floor.

Over-collateralization at 250%. The product requires $2.50 of pledged bitcoin for every $1.00 of down-payment credit — equivalent to a 40% LTV on the pledged stack. The over-collateralization is what gives the structure its safety margin: even a meaningful bitcoin drawdown still leaves the collateral well above the loan balance, which is the structural mechanic that makes the no-margin-call feature possible. The trade-off is that the pledged portion of the stack is committed to the product for the life of the loan — though early repayment of the second-lien at any point after year 3 (no prepayment penalty under QM rules) releases the pledged bitcoin in full. The 2.5× lockup is a ceiling the borrower can choose to end, not a fixed multi-decade commitment.

The economics of the bitcoin-backed second-lien typically run 0.5 to 1.5 percentage points above the standard 30-year mortgage rate. That spread is the cost of the regulated custody, the specialized monitoring, and the absence of rehypothecation revenue that subsidizes rates on CeFi BTC loans. It’s a meaningful number to model against your alternatives — especially the alternative of selling for the down-payment, where the “cost” is the forgone future appreciation (opportunity cost) of the BTC sold rather than an ongoing fiat interest rate burden.

The structural difference: no margin call

Unlike CeFi BTC-backed loans, which liquidate on price (typical 75–90% LTV trigger), this product has no price-based margin call at any drawdown level. The only liquidation trigger is 60 days of payment delinquency on the mortgage. As long as you make the monthly payments, the pledged collateral sits untouched regardless of where bitcoin’s price goes. Your liquidation risk is now driven by your ability to make monthly mortgage payments, not by bitcoin’s drawdown profile.

Three advantages of pledging bitcoin collateral instead of selling bitcoin

The fiscal mechanics behind why a bitcoiner would prefer this product to selling for a down payment break down into three distinct benefits.

The compliance reality

Standard mortgage compliance applies, plus the IRS requires loan-tracing documentation for the second-lien proceeds (which the servicer provides as part of normal onboarding). The structure is specifically designed to avoid constructive-sale treatment under §1259 of the IRS code: no mandatory price-based hedges, no market-driven liquidations, no margin call. Your accountant and the servicer cover the compliance work — it’s routine, not specialized. The bitcoin-collateral piece doesn’t meaningfully increase paperwork beyond what a conventional second-mortgage borrower already does.

What about counterparty risk?

The 250% over-collateralization and segregated-account custody framework substantially reduce, but don’t eliminate, counterparty risk on the pledged bitcoin. Three distinct counterparties hold the structure together, and the failure mode of each is structurally different from the prior decade’s CeFi precedents.

The structural advantage versus the prior decade of CeFi bitcoin-backed lending isn’t that counterparty risk has been eliminated — it’s that the custody framework is built around segregation rather than commingling, the servicer sits inside a federally regulated mortgage-servicing industry rather than an unregulated lending platform, and the collateral mechanism explicitly excludes rehypothecation. The failure mode that defined the prior decade — force-liquidation or loss of segregated-but-actually-commingled collateral — isn’t the failure mode of this structure.

Model it: Pledge vs. Sell over time

The decision lives in the trade-off between two costs that move in opposite directions over the horizon: the cumulative interest cost of the pledge path (a known, dollar-denominated cost that grows linearly with time and stops at any early-repayment year), and the opportunity cost of the BTC you’d have sold (an unknown, bitcoin-denominated cost that grows with whatever trajectory bitcoin produces). The calculator below sets future bitcoin price to the Power Law trend at end of horizon§Modelling note · Power Law as central tendencyThe Power Law trend is a central-tendency expectation, not a forecast. Bitcoin spends roughly half its time above the trend and half below, with deviations large in either direction during cycles. Use the trend as the conceptual midpoint; remember that an actual outcome inside any specific horizon could be meaningfully higher or lower. The Power Law page covers the model and its uncertainty bands. — a central-tendency expectation, not a forecast — and shows the cumulative cost of each path using a simple-interest model§Modelling note · Simple-interest approximationThe cumulative pledge-path cost is modelled as (downPayment × rate + homePrice × premium) × min(years, repayYear) — a straight-line approximation that slightly overstates the true cost, because in amortizing loans the outstanding balance (and therefore interest charged) declines over time. The two terms reflect (a) the base-rate interest on the down-payment portion that the sell path doesn’t borrow at all, and (b) the BBM rate premium applied to the full mortgage per Coinbase’s product structure. Matches the convention used on the parent Borrowing Against Your Stack calculator. For exact figures, run a full amortization schedule with your lender.. The interest on both loans may be tax-deductible depending on loan-tracing§Regulatory note · Interest deductibilityMortgage interest on the primary loan is deductible under home-acquisition rules. The second-lien also generally qualifies as acquisition debt if the proceeds are documented as funding the down payment specifically — the IRS loan-tracing rules place the documentation burden on the borrower. Calculator outputs do not net out the value of the deduction; model it separately against your bracket and the standard-deduction comparison. — the calculator shows pre-deduction figures.

How this fits inside the broader argument

The case for pledging instead of selling is, at root, the case for not trading bitcoin’s long-duration appreciation for a one-time fiat outlay. If you believe bitcoin’s compound annual growth rate over the duration of a 30-year mortgage will exceed your cost of debt — the central Power Law claim — then every coin sold today is a coin compounding for someone else, instead of for you. The bitcoin-backed mortgage exists because that case held up structurally for years but had no regulated vehicle to express it; the Fannie-Mae-conforming product is the first one that does, with the additional feature of removing margin-call risk from the mechanic.

The full hierarchy of bitcoin-backed lending categories sits on the Borrowing Against Your Stack page. Mortgages sit on the “serious consideration” tier alongside collaborative-custody multisig and Tier-1 non-rehypothecating CeFi.

However, the above seeming benefits do not come without cost. The principal cost is counterparty risk at three layers — Fannie Mae, Better Home & Finance, and Coinbase Prime — each manageable in isolation but cumulatively a real exposure that simply not taking the loan would avoid entirely (see What about counterparty risk? earlier on this page). The product also requires 2.5× over-collateralization of the pledged stack — atypical for traditional secured loans, where the loan-to-value on the underlying asset typically runs 80% or higher — and locks up bitcoin for as long as the second-lien remains outstanding (short of retiring the lien early, subject to any defined costs). The honest comparison isn’t only against the sell path; it’s also against the borrow-nothing path, which carries neither of these costs.

What the product brings in return is a rate that, while higher than a vanilla 30-year mortgage, is materially lower than the closest bitcoin-collateralized alternatives, and a scenario that can be argued to be more advantageous over the long term vs. selling bitcoin outright to fund the down-payment. Collaborative-custody multisig BTC loans typically run 12–16% APR; Strike’s bitcoin-backed loans run roughly 7.5–10.5% APR depending on loan size; this product runs the standard 30-year rate plus 0.5 to 1.5pp — regularly the lowest-priced offering in the no-rehypothecation tier.

As with the rest of the site, the right reading isn’t “this is the answer.” The right reading is: here’s the structural detail you need to evaluate whether it’s the answer for your specific situation. If the structural fit lines up and the costs above are ones you’ve weighed honestly, this is the cleanest version of the borrow-against-bitcoin approach currently available in the US regulated tier for funding a home purchase. If it doesn’t, the page has done its job by helping you walk away on reflection.