Liquidation is the mechanism that makes overcollateralized lending work without trusting anybody. It is also the thing that costs careless borrowers money. Both facts are worth understanding in detail, because the second one is almost entirely avoidable.
The problem liquidation solves
A lending protocol has no legal recourse. It cannot sue you, garnish your wages, or report you to a credit bureau. If your debt ever exceeds your collateral, that shortfall is simply a hole in the protocol's balance sheet — and the borrower's rational move is to walk away and keep the borrowed funds.
So the protocol has to guarantee, mechanically, that this never happens. It does that by selling your collateral before it becomes insufficient, while there is still a buffer.
That sale is a liquidation. It is not a penalty for bad behaviour. It is the protocol closing a risk it is not allowed to hold.
The three numbers that decide everything
Loan-to-value (LTV) — your debt divided by the value of your collateral. This is the number you watch.
Maximum LTV — the ceiling on new borrowing. You cannot mint past it.
Liquidation threshold — the LTV at which your position becomes eligible for liquidation. It sits above the maximum LTV, and the gap between them is the buffer the protocol gives you to react.
A worked example. You deposit $10,000 of collateral and borrow $4,000. Your LTV is 40%.
- Collateral falls 20% → worth $8,000 → LTV rises to 50%.
- Collateral falls 40% → worth $6,000 → LTV rises to 67%.
- Collateral falls 50% → worth $5,000 → LTV rises to 80%.
Notice the acceleration. LTV rises faster than the collateral falls, because the debt side is fixed while the denominator shrinks. This is why positions that look comfortable at a 15% drawdown can be in serious trouble at 35%, and it is the single most under-appreciated fact about collateralized borrowing.
Your liquidation price is the collateral price at which your LTV hits the threshold. It is worth knowing that number for every open position, and the app calculates it for you.
Who actually buys your collateral
Somebody has to be on the other side of a forced sale, immediately, at scale, during exactly the market conditions where nobody wants to buy anything. Different protocols solve this differently, and the design has real consequences for how much a liquidation costs you.
Fixed-discount liquidation is the classic model: any liquidator can repay your debt and claim your collateral at a fixed discount to market — typically somewhere in the 5–15% range. Simple, but the discount is set in advance and applies whether or not competition would have driven it lower.
Auction-based liquidation runs a live auction for the collateral. Better price discovery, but it takes time, and time is the one thing a crashing market does not give you.
Bid-queue liquidation — the model Solid inherits from the Anchor lineage — inverts it. Liquidators pre-commit capital into a queue of discount tiers, bidding in advance on collateral that has not been liquidated yet. When a position crosses the threshold, it fills against the queue starting at the smallest discount that has capital waiting.
The consequence for a borrower is worth stating plainly: competition among liquidators is what determines your penalty. If liquidators have queued capital at a low discount tier, that is the discount you pay. A deep, competitive queue is a borrower's friend, not a threat.
What a liquidation actually costs you
You do not lose your whole position. You lose the discount on the portion that was liquidated.
Say $2,000 of your debt gets repaid by a liquidator taking collateral at a 10% discount. They receive roughly $2,222 of collateral for repaying $2,000 of your debt. Your loss is that ~$222 spread, plus whatever the collateral would have been worth had you sold it yourself, calmly, later.
That last part is usually the bigger cost. Liquidations cluster at market lows, because that is definitionally when they trigger. You are force-selling at the worst price of the cycle, and unlike a discretionary sale you get no say in the timing.
Five ways to never be liquidated
- Borrow well below the maximum. The single highest-leverage decision, made once, at the start. If the ceiling is high, that is a capability, not a recommendation.
- Know your liquidation price by heart. Not your LTV — the collateral price that triggers it. LTV is abstract; a price is something you can watch.
- Account for interest drift. Your debt grows continuously. A position opened at a safe LTV and never touched will drift toward the threshold on its own.
- Keep dry powder for the collateral side. Adding collateral during a drawdown is usually cheaper and faster than sourcing stablecoins to repay.
- Decide your action in advance. Write down the LTV at which you will add collateral or repay, before you open the position. Panic is a poor risk manager.
Why this design is worth trusting
There is a version of this article that treats liquidation as a hazard to be feared. That framing is backwards.
Liquidation is the reason an overcollateralized stablecoin can exist without a bank, an issuer, or a promise. It is the mechanism that keeps every unit of SOLID backed by more than a dollar of collateral, automatically, without anybody's permission or good faith. The protocol's solvency does not rest on trust — it rests on the arithmetic being enforced before the buffer is gone.
The borrowers who get hurt by it are, almost without exception, the ones who borrowed at the ceiling. The mechanism is loud and public about where the line is. Staying away from it is a choice available to everyone.
FAQ
What triggers a liquidation?
Your loan-to-value ratio crossing the liquidation threshold. That happens when your collateral falls in value, when your debt grows through accrued interest, or both together.
Do I lose all my collateral in a liquidation?
No. Only enough collateral is sold to bring your position back within safe bounds, and you keep the remainder. Your loss is the liquidation discount applied to the portion that was sold, plus the effect of selling at a market low.
What is a liquidation penalty?
The discount at which liquidators acquire your collateral. In a bid-queue system that discount is set by competition among liquidators who pre-commit capital at different tiers, so the effective penalty depends on how deep the queue is at the time.
Can I stop a liquidation once it starts?
Not once the transaction is on-chain. You can prevent it beforehand by repaying debt or adding collateral to push your loan-to-value back below the threshold, which is why watching your liquidation price matters more than reacting to alerts.
Does interest alone cause liquidations?
Yes, over a long enough period. Debt accrues continuously, so an untouched position drifts to a higher loan-to-value even if the collateral price never moves. Positions opened close to the ceiling are the most exposed to this.