A deterministic protocol for frictionless trade processing of financial contracts
|Christian Fries (@cfries), Peter Kohl-Landgraf (@pekola), Alexandros Korpis (@kourouta)
Table of Contents
- Test Cases
- Reference Implementation
- Security Considerations
The Smart Derivative Contract (SDC) allows fully automizing and securing a financial product’s - e.g. a financial derivative or bond - complete trade life cycle. The SDC leverages the advantages of smart contracts to remove many of the frictions associated with the classical derivative life cycle. Most notably, the protocol allows the removal of counterpart risk essentially. The SDC can be implemented using a pre-agreed valuation oracle and valuation model, removing ambiguity in the settlement amounts. The SDC provides methods and callbacks to enable fully automated and fully transactional settlements (delivery-versus-payment, payment-vs-payment). Token-based settlement can be realized by any contract implementation implementing an ERC-20 token. Proof of concepts in terms of two legally binding digital Interest Rate Swaps were conducted in 2021 and 2022.
By their very nature, so-called “over-the-counter (OTC)” financial contracts are bilateral contractual agreements on exchanging long-dated cash flow schedules. Since these contracts change their intrinsic market value due to changing market environments, they are subject to counterparty credit risk when one counterparty is subject to default. The initial white paper describes the concept of a Smart Derivative Contract (SDC) with the central aim to detach bilateral financial transactions from counterparty credit risk and to remove complexities in bilateral post-trade processing by a complete redesign.
A Smart Derivative Contract is a deterministic settlement protocol with the same economic behaviour as a Financial Contract - e.g. an OTC-Derivative or a Bond. Every process state is specified; therefore, the trade and post-trade process is known in advance and is deterministic over the trade’s life cycle. An ERC-20 token can be used for frictionless decentralized settlement, see reference implementation. We do provide a separate interface and implementation for a specific “Settlement Token” derived from ERC-20. These features enable two or multiple trade parties to process their financial contracts fully decentralized without relying on a third central intermediary agent. The process logic of SDC can be implemented as a finite state machine on solidity.
The interface’s life cycle functionality applies to several use cases.
In the case of a collateralized OTC derivative, an SDC settles the outstanding net present value of the underlying financial contract on a frequent (e.g. daily) basis. With each settlement cycle, the net present value of the underlying contract is exchanged, and the value of the contract is reset to zero. Pre-agreed margin buffers are locked at the beginning of each settlement cycle so that settlement will be guaranteed up to a certain amount. If a counterparty fails to obey contract rules, e.g. not providing sufficient pre-funding, SDC will terminate automatically with the guaranteed transfer of a termination fee by the causing party. We provide a Reference Implementation for this case.
A defaultable OTC Derivative has no Collateral Process in place. In that case, a smart derivative will settle the according cash flows as determined in the derivative contract specification. A defaultable OTC derivative might end in a state ‘Failure to Pay’ if a settlement cannot be conducted.
The life cycle of a bond can also make use of the function catalogue below. The interface enables the issuer to allocate and redeem the bond as well as settle coupon payments. On the other hand, it allows bondholders to interact with each other, conducting secondary market trades. It all boils down to a settlement phase, which needs to be pre-agreed by both parties or triggered by the issuer which can be processed in a completely frictionless way.
The following methods specify a Smart Derivative Contract’s trade initiation and settlement life cycle. For further information, please also look at the interface documentation ISDC.sol.
A party can initiate a trade by providing the party address to trade with, trade data, trade position, payment amount for the trade and initial settlement data. Only registered counterparties are allowed to use that function.
function inceptTrade(address _withParty, string memory _tradeData, int _position, int256 _paymentAmount, string memory _initialSettlementData) external;
A counterparty can confirm a trade by providing its trade specification data, which then gets matched against the data stored from
function confirmTrade(address _withParty, string memory _tradeData, int _position, int256 _paymentAmount, string memory _initialSettlementData) external;
Allows eligible participants (such as counterparties or a delegated agent) to trigger a settlement phase.
function initiateSettlement() external;
Valuation may be provided on-chain or off-chain via an external oracle service that calculates the settlement or coupon amounts and uses external market data. This method serves as a callback called from an external oracle providing settlement amount and used settlement data, which also get stored. The settlement amount will be checked according to contract terms, resulting in either a regular settlement or a termination of the trade.
function performSettlement(int256 settlementAmount, string memory settlementData) external;
This method - either called back from the provided settlement token directly or from an eligible address - completes the settlement transfer. This might result in a termination or start of the next settlement phase, depending on the provided success flag.
function afterTransfer(uint256 transactionHash, bool success) external;
Allows an eligible party to request a mutual termination with a termination amount she is willing to pay
function requestTradeTermination(string memory tradeId, int256 _terminationPayment) external;
Allows an eligible party to confirm a previously requested (mutual) trade termination, including termination payment value
function confirmTradeTermination(string memory tradeId, int256 _terminationPayment) external;
The following events are emitted during an SDC Trade life-cycle.
Emitted on trade inception - method ‘inceptTrade’
event TradeIncepted(address initiator, string tradeId, string tradeData);
Emitted on trade confirmation - method ‘confirmTrade’
event TradeConfirmed(address confirmer, string tradeId);
Emitted when a Trade is activated
event TradeActivated(string tradeId);
Emitted when a settlement is requested. May trigger the settlement phase.
event TradeSettlementRequest(string tradeData, string lastSettlementData);
Emitted when the settlement phase is started.
Emitted when termination request is initiated by a counterparty
event TradeTerminationRequest(address cpAddress, string tradeId);
Emitted when termination request is confirmed by a counterparty
event TradeTerminationConfirmed(address cpAddress, string tradeId);
Emitted when trade is terminated
event TradeTerminated(string cause);
Emitted when trade processing stops.
The interface design and reference implementation are based on the following considerations:
- An SDC protocol enables interacting parties to initiate and process a financial transaction in a bilateral and deterministic manner. Settlement and Counterparty Risk is managed by the contract.
- The provided interface specification is supposed to completely reflect the entire trade life cycle.
- The interface specification is generic enough to handle the case that parties process one or even multiple financial transactions (on a netted base)
- Usually, the valuation of financial trades (e.g. OTC Derivatives) will require advanced valuation methodology to determine the market value. This is why the concept might rely on an external market data source and hosted valuation algorithms
- A pull-based valuation-based oracle pattern can be implemented by using the provided callback pattern (methods:
- The reference implementation
SDC.solis based on a state-machine pattern where the states also serve as guards (via modifiers) to check which method is allowed to be called at a particular given process and trade state
An abstract contract class SDC.sol as well as a full reference implementation SDCPledgedBalance.sol for an OTC-Derivative is provided and is based on the ERC-20 token standard.
/assets/contracts, more explanation on the implementation is provided inline.
Please take a look at the provided xml file as a suggestion on how trade parameters could be stored.
No known security issues up to now.
Copyright and related rights waived via CC0.
Please cite this document as:
Christian Fries (@cfries), Peter Kohl-Landgraf (@pekola), Alexandros Korpis (@kourouta), "ERC-6123: Smart Derivative Contract [DRAFT]," Ethereum Improvement Proposals, no. 6123, December 2022. [Online serial]. Available: https://eips.ethereum.org/EIPS/eip-6123.