State Transitions

State Transitions

This document describes the state transition operations pertaining to:

• Creating an insurance fund
• Underwriting an insurance fund
• Request a redemption from the insurance fund
• Automatic processing of matured redemption requests

Creating insurance fund

Params description Sender field describes the creator of an insurance fund . Ticker, QuoteDenom, OracleBase, OracleQuote, OracleType, Expiry fields describe the derivative market info that the insurance fund associated to. InitialDeposit field describes the initial deposit amount to be put on the insurance fund.

Steps

• Get MarketId for the insurance fund - Note, market could be not available yet on exchange and it’s not an issue
• Ensure if insurance fund associated to the MarketId does not exist
• Ensure if initial deposit amount is not zero
• Get shareDenom that is unique - it’s incremented when share denom is requested for insurance fund creation or when underwriting insurance fund that has zero balance and non-zero total share denom supply.
• Send coins from creator’s account to insurance fund module account
• Create insurance fund object with DefaultRedemptionNoticePeriodDuration and with the params provided
• Set Balance of fund object to initial deposit amount
• Mint InsuranceFundInitialSupply (10^18) shareDenom tokens to creator account
• Save insurance fund object to store
• Register newly created insurance fund shareDenom metadata inside BankKeeper

Underwriting an insurance fund

Params description Sender field describes the underwriter of an insurance fund . MarketId field describes the derivative market id to the insurance fund. Deposit field describes the deposit amount to be added on the insurance fund.

Steps

• Ensure if insurance fund associated to the MarketId does exist
• Send underwriting tokens from sender’s account to module account
• Make actions based on the status of insurance fund associated to the MarketId.
  • A. when Balance and ShareDenomSupply are zero
    1. mint InsuranceFundInitialSupply (10^18) to the sender.
    2. set Balance to deposit amount
    3. set ShareDenomSupply to InsuranceFundInitialSupply
  • B. when Balance is zero and ShareDenomSupply is not zero
    1. change ShareDenom of the the insurance fund to start new insurance fund from beginning.
    2. register newly created ShareDenom in bank keeper
    3. mint InsuranceFundInitialSupply (10^18) to the sender.
    4. set Balance to deposit amount
    5. set ShareDenomSupply to InsuranceFundInitialSupply
  • C. when Balance is not zero and ShareDenomSupply is zero
    1. mint InsuranceFundInitialSupply (10^18) to the sender.
    2. increase Balance by deposit amount
    3. set ShareDenomSupply to InsuranceFundInitialSupply
  • D. when both Balance and ShareDenomSupply are not zero - normal case
    1. increase Balance by deposit amount
    2. mint prev_ShareDenomSupply * deposit_amount / prev_Balance amount of ShareDenom to sender
    3. increase ShareDenomSupply with mint amount
• Save insurance fund object to store

Requesting a redemption from an insurance fund

Params description Sender field describes the redemption requester of an insurance fund . MarketId field describes the derivative market id associated to the insurance fund. Amount field describes the share token amount to be redeemed.

Steps

• Ensure insurance fund associated to the MarketId does exist
• Send ShareDenom to module account
• Get new redemption schedule ID
• Calculate ClaimTime from insurance fund’s redemption notice period duration and current block time
• Calculate key to store pending redemption (redemption schedule)
• Create redemption schedule object with details
• Store redemption schedule object to store

Insurance fund actions on liquidation events in derivative market

Steps

• exchange module finds relative insurance fund from the insurance keeper.
• if missingFund is positive, it withdraws the amount from the insurance fund through WithdrawFromInsuranceFund.
• if missingFund is negative, it deposits the amount into the insurance fund through DepositIntoInsuranceFund.

Automatic processing of pending redemptions

Steps

Iterate all matured redemptions by sorted order by ClaimTime and perform the following actions:

• If ClaimTime is after current block time, break early
• Ensure the insurance fund exist for matured redemption schedule
• Calculate redeem amount from share amount - shareAmt * fund.Balance * fund.TotalShare
• Send calculate redeem amount from module account to redeemer account
• Burn share tokens sent to the module account at the time of redemption schedule
• Delete redemption schedule object
• Reduce insurance fund’s Balance by redeem amount
• Store updated insurance object to store

Hooks

Other modules may register operations to execute when a certain event has occurred within insurance fund. These events can be registered to execute either right Before or After the exchange event (as per the hook name). The following hooks can registered with the exchange:

Note: Hooks are not available and exchange module calls insurance keeper function directly.

Steps When liquidation event happen in derivative market

• exchange module finds relative insurance fund from the insurance keeper.
• if missingFund is positive, it withdraws the amount from the insurance fund through WithdrawFromInsuranceFund.
• if missingFund is negative, it deposits the amount into the insurance fund through DepositIntoInsuranceFund.