There is a specific problem crypto-backed lending is built to solve. You hold ETH, you believe in holding it, and you need dollars. Selling solves the cash problem and creates two others: you give up the position, and in most jurisdictions you trigger a taxable disposal.
Borrowing stablecoins against that ETH keeps the position and provides the liquidity. It also introduces a risk that selling does not have: your collateral can be liquidated. This article explains the mechanics honestly, including the parts that marketing copy tends to leave out. If you read only one section, read the one on liquidation.
Why Borrow Rather Than Sell
The case for borrowing rests on three things:
- Retained exposure. If ETH appreciates while your loan is outstanding, you keep the upside. If it falls, you keep the downside too, which is the part that matters for liquidation.
- No disposal event. In many tax systems, borrowing against an asset is not a sale and does not crystallize a gain. This varies significantly by jurisdiction and is not universal, so treat it as a question for a tax professional rather than a settled fact.
- Flexibility. A credit line you draw against as needed behaves differently from a one-time loan, and often costs less if you only need money intermittently.
The case against is equally simple. Selling is final and certain. Borrowing keeps you exposed to price movement while adding an obligation with a deadline and a forced-sale mechanism attached. Which is better depends entirely on whether you can service the loan through a drawdown.
How Collateralized Lending Works Mechanically
Almost every onchain lending product follows the same shape:
- You deposit ETH into a smart contract as collateral. On a non-custodial platform, you approve the transaction from your own wallet and the platform does not hold your keys.
- An oracle reports the ETH price to the contract. This is the single most important dependency in the system, because everything else is calculated from it.
- The contract calculates your borrowing capacity as a percentage of collateral value.
- You draw stablecoins, commonly USDC, up to that capacity.
- Interest accrues on what you have drawn, not on your total capacity.
- The contract continuously monitors your loan-to-value ratio. If it crosses a threshold, collateral is sold automatically to repay the debt.
- You repay to reduce the debt and, once cleared, withdraw your collateral.
No credit check, no income verification, no human underwriter. The collateral is the underwriting. That is what makes it fast, and also what makes the liquidation mechanism non-negotiable.
Collateral Requirements and the Terms That Govern Them
Five terms determine your actual risk. Learn them before you deposit anything.
| Term | What it means in practice |
|---|---|
| Loan-to-value (LTV) | Debt divided by collateral value. Deposit $10,000 of ETH, borrow $4,000, and your LTV is 40%. LTV rises when you borrow more or when ETH falls. |
| Maximum opening LTV | The highest LTV at which you are allowed to draw. This is your borrowing capacity, and it is deliberately set below the liquidation threshold to leave headroom. |
| Liquidation threshold | The LTV at which the contract begins selling collateral. The gap between your opening LTV and this number is your entire buffer against a price drop. |
| Liquidation penalty | A fee taken from collateral when liquidation occurs, on top of the debt repaid. This is why liquidation is expensive rather than merely inconvenient. |
| Origination fee | A one-time charge for opening the line or drawing funds. It is separate from interest and is generally not waived by promotional interest terms. |
The arithmetic that matters: if you borrow at 50% LTV and liquidation triggers at 80% LTV, ETH can fall roughly 37% before you are liquidated. Borrow at 70% against the same threshold and the tolerable drop shrinks to about 12%. ETH has moved more than 12% in a single day on multiple occasions. Your opening LTV is the most consequential decision you make, and it is entirely yours.
Illustrative figures only. Actual maximum LTV, liquidation thresholds and penalties differ by platform and by collateral asset, and are sometimes adjusted. Read the platform’s published parameters rather than assuming an industry standard.
Credit Lines Versus One-Time Loans
A one-time loan issues a fixed amount and starts charging interest on all of it immediately. A credit line approves a capacity you draw against, and charges interest only on the drawn portion. If your need is recurring or uncertain in size, the difference is material.
A concrete illustration of the distinction: a borrower with a 20,000 USDC limit who has used 5,000 USDC has 15,000 USDC still available, and carries debt of 5,000 USDC rather than 20,000. Repaying principal restores the corresponding available credit, so the same line can be drawn again without opening a new loan.
One nuance that catches people out is the repayment waterfall. Payments are not applied straight to principal. A typical ordering applies funds to penalties first, then accrued interest, then unpaid fees, and only then principal. Since only the principal portion reduces your debt and restores available credit, a payment made while penalties are outstanding may barely move your LTV.
How Interest Is Actually Calculated
Onchain interest usually accrues continuously against the drawn balance, rather than in monthly instalments. There is generally no fixed schedule of payments and no fixed maturity date; the loan persists until you repay it or it is liquidated.
Two distinctions worth understanding:
- Variable versus fixed rates. Many protocols set rates algorithmically based on how much of the available liquidity is being borrowed. A rate you saw at opening can change, sometimes substantially, without notice.
- Simple versus compounding accrual. Compounding accrual adds unpaid interest to the balance it is charged on. Over a long-held position the difference is not trivial.
A worked example with every assumption stated:
| Input | Value | Note |
|---|---|---|
| ETH collateral deposited | $20,000 | Illustrative |
| Maximum opening LTV | 50% | Platform parameter; varies |
| Available credit | $10,000 | 50% of collateral value |
| Amount actually drawn | $4,000 | Interest applies to this, not to $10,000 |
| Annual interest rate | 9% | Assumed and variable in practice |
| Interest over 30 days | about $29.59 | $4,000 x 9% x 30/365, simple accrual |
| Origination fee at 1% | $40 | One-time, charged on the drawn amount |
| Total 30-day cost | about $69.59 | Fee exceeds a month of interest here |
Note what that example shows. On a short hold, the one-time fee costs more than the interest. Any comparison of borrowing costs that looks only at the advertised rate will mislead you on short-duration borrowing.
What “0% Interest” Does and Does Not Mean
Several platforms now offer a grace period during which interest does not accrue if the drawn amount is fully repaid in time. This is a genuine feature and it can genuinely reduce cost. It is also the claim most often misread.
Three things a grace period does not do:
- It does not waive the origination fee or other applicable charges. Zero interest is not zero cost.
- It does not suspend LTV rules. Your position can still be restricted or liquidated during the grace period if collateral value falls far enough. This is the critical point, because the phrase “0% interest” creates a false sense of safety.
- It does not apply to amounts repaid late. Miss the window and interest accrues under the standard terms.
As a current example of this structure, XQ Finance is building a wallet-based, non-custodial ETH-backed USDC credit line with the line managed on Base and collateral supported on Ethereum or Base. Its published terms include a 14-day grace period: if the borrower fully repays the used amount within that window, interest does not accrue on that amount for the period. Its own documentation is explicit that the origination fee and other charges are not removed by the grace period, and that the grace period does not suspend LTV rules or protect a position from liquidation.
Two caveats worth knowing before you plan around it. XQ states that the product is under development and that its documentation describes a planned MVP that may change before public launch, so it is not a live facility you can draw on today. And its product terms page, which is where the origination fee, interest rates and other parameters will be listed, is still being prepared, meaning the full cost structure is not yet published. Anyone evaluating it should read the xq finance documentation directly, and check whether those parameters have been published, rather than relying on a summary written before launch.
Repayment Terms
Most onchain credit lines have no scheduled instalments. You repay when you choose, in the borrowed asset, and partial repayment is normally permitted. What replaces the payment schedule is the LTV requirement, which is a harder constraint than a due date because it can be breached by something you do not control.
Practical implications:
- Keep stablecoins in reserve. The ability to repay quickly, or to add collateral, is your defence against liquidation in a falling market.
- Understand that repaying into a grace period deadline requires the transaction to confirm before the deadline, not to be submitted before it.
- Check whether repayment restores available credit or closes the line, since these are different products.
- Confirm what is required to withdraw collateral: typically all principal, interest, fees and penalties cleared.
Blockchain Fees
Gas is a real cost and it is easy to underestimate because it is charged in ETH, not in the stablecoin you borrowed.
- You will pay gas on multiple transactions: token approval, collateral deposit, opening the line, each draw, each repayment, and collateral withdrawal.
- Layer 2 networks such as Base cost a small fraction of Ethereum mainnet for the same operation, which is a large part of why lending products are deploying there.
- You must hold ETH on the correct network to pay gas. Holding ETH on mainnet does not let you transact on Base. Being unable to afford gas on the network where your loan lives is a genuine failure mode during a liquidation scare.
- Bridging assets between networks costs money and takes time, and time is exactly what you lack in a fast drawdown.
- Gas prices spike during volatility, which is precisely when you may need to repay or top up collateral urgently.
The Risks, Stated Plainly
| Risk | How it happens | What reduces it |
|---|---|---|
| Liquidation | ETH falls, LTV crosses the threshold, collateral is sold automatically plus a penalty | Borrow at conservative LTV; hold reserves to repay or top up; set your own alerts well before the threshold |
| Oracle failure or manipulation | The contract acts on a wrong price and liquidates a position that was never actually underwater | Prefer platforms using established oracle infrastructure with documented safeguards |
| Smart contract exploit | A bug or attack drains collateral. This has happened repeatedly across DeFi and losses are usually unrecoverable | Independent audits, time in production, bug bounties, and never depositing more than you can lose |
| Stablecoin depeg | The borrowed stablecoin trades away from $1, changing the real value of your debt | Understand the issuer, reserve composition and redemption mechanism of the specific stablecoin |
| Rate changes | A variable rate rises and your cost of carry increases on an open position | Model the position at materially higher rates before opening it |
| Liquidity shortfall | Insufficient stablecoin liquidity in the pool prevents you drawing when you need to | Do not treat an available limit as a guaranteed emergency facility |
| No deposit protection | There is no FDIC, FSCS or equivalent insurance. If the platform fails you may have no recourse | Size positions accordingly; this risk cannot be mitigated away |
| Tax on liquidation | A forced sale of collateral is generally a disposal, creating a tax liability from an event you did not choose | Discuss with a tax professional before opening a leveraged position |
| Regulatory change | Rules on lending, stablecoins and custody are actively evolving across jurisdictions | Follow developments in your own jurisdiction |
| The liquidation cascade is the risk people underestimate Liquidation is not a neutral unwinding. You lose the collateral sold, you pay a penalty on top, and the sale happens at the worst price in the cycle rather than at a moment of your choosing. If you borrowed to avoid selling at a low price, being liquidated delivers precisely the outcome you were trying to avoid, with an additional fee attached. Then, in most tax systems, the forced sale is still a disposal. Assume ETH can fall 30 to 50% from any starting point, because it has, repeatedly, and size the position so that such a move does not liquidate you. |
Due Diligence Before You Deposit
- Read the published parameters: maximum LTV, liquidation threshold, liquidation penalty, origination fee, interest rate and whether it is variable.
- If any of those are not published, treat that as material. An unpublished fee schedule is not a small gap.
- Check whether the platform is live, in beta, or pre-launch. Documentation describing a planned product is not a product.
- Look for independent smart contract audits, who performed them, and whether findings were resolved.
- Confirm the contracts are non-custodial and understand exactly which approvals you are granting from your wallet.
- Identify which oracle supplies prices and what happens if it fails or stales.
- Find out whether parameters can be changed by an administrator or governance process, and with what notice.
- Test with a small amount first, through a full cycle of draw and repayment, before committing meaningful collateral.
The Bottom Line
Crypto-backed lending is a legitimate tool with a narrow, well-defined use: you need liquidity, you want to keep your ETH exposure, and you have both the reserves and the discipline to manage a collateralized position through volatility. Credit lines that charge interest only on drawn amounts, with a grace period, can make short-term borrowing genuinely cheap.
It is a poor tool for the opposite case: borrowing at high LTV because you are confident the price will rise, with no reserve and no plan for a 40% drawdown. That is leverage, not liquidity management, and the liquidation engine does not care about your conviction.
Judge any platform on its published parameters, its audit history, its oracle design and whether it is actually live. Judge a “0% interest” claim by reading what the fee schedule says, not what the headline says.
This article is general information about how crypto-backed lending products work. It is not financial, investment, legal or tax advice, and it is not a recommendation to use any platform or product mentioned. Digital assets are volatile and borrowing against them can result in the total loss of your collateral. Platform terms cited reflect publicly available documentation at the time of writing and may change; verify current terms directly with the provider. Consult qualified professionals about your own circumstances and tax position before borrowing against digital assets.
