Bond Pool （TAC）- Testnet

Overview

The Bond Pool is a collateral-based pool on the Wing Finance platform, built on the TAC. Unlike the previous floating interest rate, the APR (Annual Percentage Rate) is set by the bond issuer based on their funding needs and will not change mid-term. This stability allows bond buyers to better calculate their returns.

Supported Assets

All supported assets are on the TAC. For detailed trading instructions, please refer to the guide here.

To Be Determined

Below is the list of tokens supported by the Bond Pool (Tac). Details of each token's transactions and smart contracts can be accessed via the blockchain explorer and token addresses on the TAC:

To Be Determined

bToken

bToken represents ownership of the assets provided to the Wing Bond Pool.These tokens are issued to users who deposit assets into the pool, acting as proof of their share in the pool. Each bToken corresponds to a supported asset on the TAC. The number of bTokens held reflects the amount of underlying collateral a user has deposited. Transaction details for each bToken can be accessed on the TAC chain via token addresses and smart contracts. Currently, bTokens support types of assets on the TAC: To Be Determined Transaction details for each bToken can be accessed on the TAC, and token addresses are as follows: To Be Determined

Interest Calculation

Interest calculations are essential for both bond issuers and subscribers. Here’s a simplified explanation:

1. APR Definition The APR (Annual Percentage Rate) is the annual interest rate that bond issuers pay to bondholders. This rate is set by the issuer and must be at least 3% for bonds in the Wing Bond Pool. The APR remains fixed for the bond’s duration.

2. Interest Calculation Formula Interest paid by the bond issuer is calculated using the following formula: WING received = Number of Bonds purchased by the subscriber / 1+APR×(MaturityDate−CurrentDate)/3651+APR×(MaturityDate−CurrentDate)/365 Interest = WING received × APR × (Maturity Date - Current Date) / 365

3. Example Assume a bond issuer issues 200 Bond-WING bonds, with WING priced at 4 USDT, an APR of 3%, and the borrowing period is 100 days:

4. • WING received = 200 / 1+31+3 ≈ 198.37 WING

   • Interest = 198.37 WING × 3% × (100 / 365) ≈ 1.63 WING

In this scenario, the bond issuer would need to pay approximately 1.63 WING in interest over the 100-day period.

Practical Examples: Bond Issuance and Liquidation

Example 1: Bond Issuance A user wants to issue 200 Bond-WING with 1,000 USDT as collateral, and the collateral factor for USDT is 0.8. The user’s issuance limit would be calculated as follows:

• 1,000 USDT × 80% = 800 USDT

• At a WING price of 4 USDT, the issuance limit would be: 800 USDT ÷ 4 USDT = 200 Bond-WING

This means the user can issue 200 Bond-WING tokens based on their collateral.

Example 2: Liquidation Process If a bond issuer’s Health Factor falls below 1, liquidation is triggered. For example, if the issuer’s collateral is 1,000 USDT, and they’ve issued 200 Bond-WING at a WING price of 4 USDT, and the WING price rises to 5.1 USDT, the bond's value now exceeds the collateral’s value:

• 160 Bond-WING can be liquidated.

• If a user liquidates 160 Bond-WING at the new price of 5.1 USDT, they would receive: 160 × 5.1 × (1 + 8%) ≈ 881.28 USDT

This process allows the liquidator to profit while returning the collateral to bondholders.

Quick-Reference Table for Key Parameters and Risks

Parameter	Description	Value
Collateral Factor	The maximum amount a user can borrow using a specific asset as collateral. Each asset’s collateral factor is determined based on its risk profile.	Varies by asset
Health Factor	Indicates the health of a bond. If this factor drops below 1, liquidation is triggered.	> 1.2(Healthy)
Liquidation Bonus	A bonus given to liquidators who repay loans at a discount.	To Be Determined
Reserve Factor	A percentage of interest that goes to the Wing DAO Community Fund.	1%
Liquidation Fee	Charged during liquidation and deducted from the liquidated collateral value.	5%
APR Minimum	The minimum Annual Percentage Rate that bond issuers must set when issuing bonds.	3%

Gas Costs

Transaction fees may fluctuate. The amounts shown below are for reference only: To Be Determined

Parameters

Key Parameters and Formulas in Bond Pool

Collateral Factor

The collateral factor is a parameter that limits the maximum amount a user can borrow using a specific asset as collateral. Each asset in the Bond Pool has a specific value associated with its risk, which affects how it can be borrowed. As the Wing ecosystem is mature with some educated users and liquidators, the parameter calibration of the Wing Project is more aggressive. The table below shows the collateral factors for each asset. (To Be Determined)

Liquidation Bonus in Bond Pool

If a borrower's address reaches 100% of the borrowing limit, the borrower's collateral assets will be liquidated. Liquidators can repay loans at the discounts listed below to earn liquidation bonuses. (To Be Determined)

Reserve Factor in Bond Pool

The reserve factor is the percentage of the interest paid by issuers that is deposited into the Wing DAO Community Fund. At settlement, issuers must pay an additional 1% fee based on the value of the collateral.

Health Factor in Bond Pool

Health Factor (HF) = (Value of Collateral * Collateral Factor) / Total Outstanding Debt Value Healthy (Green) > 1.2; 1 < Normal (Yellow) ≤ 1.2; Dangerous (Red) ≤ 1. When the health factor is less than 1, liquidation is triggered. Health Factor (HF) Calculation Formula: Health Factor = Collateral Value * Collateral Factor / Total Value of Outstanding Debt If an issuer has multiple collaterals in the same bond, the formula for the Health Factor is: Health Factor = Collateral Value 1 * Collateral Factor 1 + Collateral Value 2 * Collateral Factor 2 + ... / Total Value of Outstanding Debt

Reserve Fee in Bond Pool

There is no reserve fee when issuers issue bonds, but they must pay the corresponding blockchain transaction fees. Subscribers need to pay a reserve fee of 3% based on the value of interest when purchasing bonds, which is collected in the underlying token. (Whether the fee is part of the reserve factor is to be determined)

Liquidation Fee

If the issuer does not repay all debts on the bond's maturity date, system-led liquidation is triggered, and the total liquidated collateral will be distributed to bondholders in proportion to their holdings. During liquidation, the system will charge a liquidation fee of 5% of the value of the liquidated collateral.

Issuance, Repayment, Trading, Redemption, and Liquidation

Issuance Process:

1. Select a bond type (e.g., Bond-WING).

2. Provide a supported digital asset as collateral.

3. The maximum bond issuance value is determined by the collateral factor.

4. Bonds will be deposited directly into the issuer’s wallet and start earning rewards.

Repayment:

• Issuers can repay bonds at any time using the underlying tokens.

• No penalties for early repayment. Failure to repay triggers system-led liquidation.

Trading:

• Bonds can be freely traded at the issuer’s set APR and number of bonds issued.

• Any user holding the corresponding underlying assets can purchase bonds.

Redemption:

• Upon bond maturity, bondholders receive either the underlying tokens or, in the case of partial repayment, a mix of tokens and collateral.

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Staking

Subscribers can stake their bonds for additional WING rewards. Issuers, however, cannot stake bonds directly. Staking rewards are calculated based on the staking period and bond type, stopping when the bond matures.

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NOTE

Flash Pool Borrowing Interest Rate Model

The APR is the annual interest rate charged to the borrower. In the Bond Pool, the APR is set by the bond issuer (borrower) and must be greater than or equal to 3%.

Mechanisms

The Wing Bond Pool encompasses issuance, trading, liquidation, staking, and redemption mechanisms.

Incentive Mechanism

First, the incentives for an asset will be distributed among the issuance pool, borrowing pool, and staking pool according to the following ratios:

Pool	Ratio
Issuance Pool	To Be Determined
Staking Pool	To Be Determined

Next, specific tokens will be allocated based on a fixed WING incentive distribution ratio. The WING incentive distribution ratio for each other asset will then be based on a competitive allocation model.

Parameters for the competitive allocation model used in calculating the WING incentive distribution for each asset: (Whether to continue using the competitive model and which types of bonds are included is to be determined)

Issuance, Repayment, Trading, Redemption, Liquidation, and Staking

Issuance

When issuing a single bond, the collateral and the borrowed underlying asset cannot be the same asset. If a user wants to issue a bond on Wing, they can only use other supported digital assets as collateral, and the type of collateral is predetermined by the system. The bond issuance value will not exceed the value of (collateral value * collateral factor).

Users need to select a bond type (loan type) based on their needs and provide at least one asset as collateral from the options provided by the system. Each asset has a collateral factor that determines the maximum amount of bonds that can be issued when using the asset as collateral. For example, if a user wants to issue a Bond-WING bond and provides 1,000 USDT as collateral, with a collateral factor of 0.8 for USDT and a current WING price of 4 USDT, the user’s issuance limit would be: 1,000 USDT * 80% = 800 USDT = 800 / 4 = 200 Bond-WING. The value of the bonds and the underlying assets are pegged at a 1:1 ratio. The collateral factors for different assets are listed here: To Be Updated

Once the bond is successfully issued, the bonds will be directly deposited into the user’s wallet in the form of tokens and will start earning incentive rewards immediately. The trading of issued bonds is unrestricted. To avoid liquidation due to token price fluctuations, it is recommended that users do not exceed 80% of the borrowing limit (use the 80% limit button).

Bond Issuance Interest Rate and Interest

The Annual Percentage Rate (APR) is the annual interest rate charged to the issuer. In the Bond Pool, the APR is set by the bond issuer (borrower) and must be at least 3%. In the Bond-WING pool, the actual interest paid by the bond issuer depends on the amount of WING paid by the subscriber when purchasing Bond-WING.

For a Bond-WING bond, the interest model for bond issuers paying subscribers is: WING received = Number of Bonds actually purchased by the subscriber / [1 + APR * (Maturity Date - Current Date) / 365 days] Interest = WING received * APR * (Maturity Date - Current Date) / 365 days

Example 1: If a bond issuer issues 200 Bond-WING, with WING priced at 4 USDT, sets an APR of 3%, and the borrowing period is 100 days, then the interest they need to pay is: WING received = 200 / [1 + 3% * (100 / 365)] ≈ 198.37 WING Interest = 198.37 * 3% * (100 / 365) ≈ 1.63 WING

Repayment

The bond issuer can repay the bond at any time using the underlying tokens of the bond. No penalties are incurred for repayment before the settlement period; bonds not repaid within the settlement period will be liquidated. This type of liquidation differs from user liquidation and is conducted by the system itself. The value of the collateral to be liquidated is slightly higher than the unpaid collateral value, and the total liquidated collateral will be distributed to bondholders proportionally.

The value of the liquidated collateral is calculated as: Liquidated Collateral Value = Unpaid Bond * WING Price * (1 + 1% + 5%) (5% is the Liquidate Fee, 1% is the Reserve Fee)

After liquidation, the issuer’s outstanding debt is reset to zero. The order of collateral liquidation follows the sequence set by the administrator.

Example 1: For a Bond-WING bond, if the bond issuer issues 200 Bond-WING with collateral of 1,000 USDT, and on the maturity date, the issuer repays 100 Bond-WING, triggering liquidation: Liquidated Collateral Value = 100 * 4 * (1 + 1% + 5%) = 424 USDT Remaining collateral of 576 USDT, and the debt is reset to zero. Compared to repaying the bond, an additional 24 USDT is paid. The remaining collateral can be carried over to the next period, allowing the issuer to issue a new series of bonds or withdraw the collateral.

Trading

After issuing bonds, the bond issuer can sell their bonds according to their set APR and the number of bonds issued during the validity period of the listing. Any user who holds the corresponding underlying assets of the bonds can purchase them.

The model for the underlying assets (loan) received by the bond issuer through selling bonds is as follows: Received underlying assets = Number of bonds sold / [1 + APR * (Maturity Date - Issuance Date) / 365]

Example 1: For Bond-WING, if a bond issuer issues 200 Bond-WING with collateral of 1,000 USDT, WING priced at 4 USDT, an APR set at 3%, and a maturity period of 100 days, and sells 100 Bond-WING before the listing expires: Received underlying assets = 100 / [1 + (3% * 100 / 365)] ≈ 99.917 WING

For bond subscribers, purchasing 100 Bond-WING bonds requires paying not only the value of the bonds themselves but also a 3% fee of the earned interest. The model is as follows: WING paid = Number of bonds actually purchased by the subscriber / [1 + APR * (Maturity Date - Current Date) / 365 days] Interest = WING paid * APR * (Maturity Date - Current Date) / 365 days Total amount paid = WING paid + Interest * 3%

Substitute into the formula: WING paid = 100 / [1 + (3% * 100 / 365)] ≈ 99.185 WING Interest = 99.185 * 3% * (100 / 365) ≈ 0.815 WING Total amount paid = 100 / [1 + (3% * 100 / 365)] + 0.815 * 3% = 99.209 WING

Liquidation

When the Health Factor of a bond falls below 1.05, the bond will appear on the liquidation list. If the Health Factor of a bond issued by the bond issuer falls below 1, liquidation will be triggered, and any user holding the corresponding underlying assets can participate in the liquidation. The maximum amount of bonds that can be liquidated from the liquidation pool is 80%.

Users participating in liquidation can receive liquidation incentives for the corresponding collateral, which is as follows: To be determined.

Example 1: For Bond-WING, if a bond issuer issues 200 Bond-WING with collateral of 1,000 USDT, WING priced at 4 USDT, and the price of WING rises to 5.1 USDT, the bond's value exceeds the collateral * collateral factor value, and the Health Factor falls below 1, triggering liquidation. A user can liquidate up to 160 Bond-WING. Suppose User 1 fully liquidates 160 Bond-WING; User 1 can obtain: 160 * 5.1 * (1 + 8%) = 881.28 USDT User 1 actually pays for 160 WING and earns 65.28 USDT based on the current price.

Staking

After purchasing bonds, subscribers can earn additional WING rewards through staking. Issuers cannot directly stake bonds. Specific rewards are calculated based on the staking period and the quantity of each type of bond, and calculation stops at the bond's maturity, with results displayed uniformly. Reward rules to be updated.

Redemption

When the bond matures, regardless of the current bondholder (issuer or purchaser), bond redemption will depend on whether all issuers have fully repaid the bond debt. If fully repaid, bondholders will receive the underlying tokens. If partially repaid, bondholders will receive the underlying tokens plus a portion of the collateral.

The formulas are as follows:

Redemption when bonds are fully repaid: Received underlying tokens = Redemption amount / Held bond amount * (My held bonds / Total issued bonds) * Total repaid WING

Redemption when bonds are not fully repaid: Received underlying tokens = Redemption amount / Held bond amount * (My held bonds / Total issued bonds) * Total repaid WING Received collateral amount = Redemption amount / Held bond amount * (My held bonds / Total issued bonds) * Liquidated collateral

Example 1: For Bond-WING, suppose the total pool issued 10,000 Bond-WING, a bond issuer issued 200 Bond-WING, WING priced at 4 USDT, APR set at 3%, with a maturity period of 100 days, and all bonds are purchased by the subscriber. At maturity, the issuer fully repays the bonds, and all issuers in the pool complete the repayment. Underlying tokens received = 200 / 200 * (200 / 10,000) * 10,000 = 200

Example 2: For Bond-WING, suppose the total pool issued 10,000 Bond-WING, a bond issuer issued 200 Bond-WING, WING priced at 4 USDT, APR set at 3%, with a maturity period of 100 days, all bonds are purchased by the subscriber, and all issuers in the pool repay a total of 8,000 Bond-WING. The collateral value is 3.5 ETH, worth 9,000 USDT. Currently, the subscriber wants to redeem all 200 Bond-WING. Received underlying tokens = 200 / 200 * (200 / 10,000) * 8,000 = 160 WING Received collateral amount = 200 / 200 * (200 / 10,000) * 3.5 = 0.07 ETH (valued at 180 USDT or 45 WING) This redemption results in: 160 WING + 0.07 ETH (worth 205 WING)