Stability Pool & Liquidations

What is the Stability Pool?

The Stability Pool is the first line of defense in maintaining system solvency. It achieves that by acting as the source of liquidity to repay debt from liquidated Vaults—ensuring that the total PXDC supply always remains backed.

When any Vault is liquidated, an amount of PXDC corresponding to the remaining debt of the Vault is burned from the Stability Pool’s balance to repay its debt. In exchange, the entire collateral from the Vault is transferred to the Stability Pool.

The Stability Pool is funded by users transferring PXDC into it (called Stability Providers). Over time Stability Providers lose a pro-rata share of their PXDC deposits, while gaining a pro-rata share of the liquidated collateral. However, because Vaults are likely to be liquidated at just below 110% collateral ratios, it is expected that Stability Providers will receive a greater dollar-value of collateral relative to the debt they pay off.

Why should I deposit PXDC to the Stability Pool?

Stability Providers will make liquidation gains and receive early adopter rewards in form of EARN tokens.

What are liquidations?

To ensure that the entire stablecoin supply remains fully backed by collateral, Vaults that fall under the minimum collateral ratio of 110% will be closed (liquidated).

The debt of the Vault is canceled and absorbed by the Stability Pool and its collateral distributed among Stability Providers.

The owner of the Vault still keeps the full amount of PXDC borrowed but loses ~10% value overall hence it is critical to always keep the ratio above 110%, ideally above 150%.

Who can liquidate Vaults?

Anybody can liquidate a Vault as soon as it drops below the Minimum Collateral Ratio of 110%. The initiator receives a gas compensation (50 PXDC + 0.5% of the Vault's collateral) as reward for this service.

How am I compensated for liquidating a Vault?

The liquidation of Vaults is connected with certain gas costs which the initiator has to cover. The cost per Vault was reduced by implementing batch liquidations of up to 160 - 185 Vaults but with the aim of ensuring that liquidations remain profitable even in times of soaring gas prices the protocol offers a gas compensation given by the following formula:

gas compensation = 50 PXDC + 0.5% of Vault's collateral (PLSX)

The 50 PXDC is funded by a Liquidation Reserve while the variable 0.5% part (in PLSX) comes from the liquidated collateral, slightly reducing the liquidation gain for Stability Providers.

How do I benefit as a Stability Provider from liquidations?

As liquidations happen just below a collateral ratio of 110%, you will most likely experience a net gain whenever a Vault is liquidated.

Let’s say there is a total of 1,000,000 PXDC in the Stability Pool and your deposit is 100,000 PXDC.

Now, a Vault with debt of 200,000 PXDC and collateral of 200,000,000 PLSX is liquidated at a price of $0.00109, and thus at a collateral ratio of 109% (= 100% * (200,000,000 * 0.00109) / 200,000). Given that your pool share is 10%, your deposit will go down by 10% of the liquidated debt (20,000 PXDC), i.e. from 100,000 to 80,000 PXDC. In return, you will gain 10% of the liquidated collateral, i.e. 20,000,000 PLSX, which is currently worth $21,800. Your net gain from the liquidation is $1,800.

Note that depositors can immediately withdraw the collateral received from liquidations and sell it to reduce their exposure to PLSX, if the USD value of PLSX is expected to decrease (for an exception see Can I withdraw my deposit whenever I want?).

How do I benefit as a Stability Provider from early adopter rewards?

First you need to open a Vault, borrow PXDC, and deposit it to the Stability Pool. After making your deposit, you will start accumulating a reward (in EARN) proportional to the size of your deposit on a continuous basis. The reward is calculated according to the rewards schedule and the kickback rate of the front end that you used for making the deposit. Rewards will be the highest for early adopters of the system.

At any point in time, you can withdraw your pending rewards to your wallet address.

Can I withdraw my deposit whenever I want?

As a general rule, you can withdraw the deposit made to the Stability Pool at any time. There is no minimum lockup duration. However, withdrawals are temporarily suspended whenever there are liquidatable Vaults with a collateral ratio below 110% that have not been liquidated yet.

What oracle are you using to determine the price of PLSX?

The protocol will utilize multiple pricing sources for PLSX on PulseChain and will be announced closer to launch.

Can I lose money by depositing funds to the Stability Pool?

While liquidations will occur at a collateral ratio well above 100% most of the time, it is theoretically possible that a Vault gets liquidated below 100% in a flash crash or due to an oracle failure. In such a case, you may experience a loss since the collateral gain will be smaller than the reduction of your deposit.

If PXDC is trading above $1, liquidations may become unprofitable for Stability Providers even at collateral ratios higher than 100%. However, this loss is hypothetical since PXDC is expected to return to the peg, so the “loss” only materializes if you had withdrawn your deposit and sold the PXDC at a price above $1.

Please note that although the system is diligently audited, a hack or a bug that results in losses for the users can never be fully excluded.

What happens if the Stability Pool is empty when liquidations occur?

If the Stability Pool is empty, the system uses a secondary liquidation mechanism called redistribution. In such a case, the system redistributes the debt and collateral from liquidated Vaults to all other existing Vaults. The redistribution of debt and collateral is done in proportion to the recipient Vault's collateral amount.

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