This article needs additional citations for verification. (May 2018) (Learn how and when to remove this template message)
A stablecoin is a cryptocurrency designed to minimize the price volatility. Stablecoins are used as stores of value or units of account, as well as in other use cases where volatile cryptocurrencies may be less desirable.
Authors of stablecoins use different designs to achieve price stability. The value of a stablecoin can be pegged to fiat currencies, or to exchange traded commodities (such as gold, silver, other precious and industrial metals, etc). Stablecoins can be centralized where they can be backed by fiat and exchange-traded commodities directly, or in a decentralized fashion via leveraging other cryptocurrency projects in different ways.
Fiat currency backed stablecoins
Stablecoins backed by fiat currencies are the most common and the oldest type of stablecoins on the market. Characteristics of fiat backed stablecoins:
- Their value is pegged to a fiat currency (most commonly the US dollar, also the Euro and the Swiss franc) in a fixed ratio,
- The tether is realized off-chain, through banks or other types of regulated financial institutions which serve as depositaries of the currency used to back the stablecoin,
- The amount of the currency used for backing of the stablecoin has to reflect the circulating supply of the stablecoin.
In technical terms, this type of stablecoins is of the simplest design. Their value is based on the value of the backing fiat currency, which is held by a third party regulated financial entity. In this setting, the trust into the custodian of the backing asset is crucial for the stability of price of the stablecoin. Fiat-backed stablecoins can be traded on exchanges and are redeemable from the issuer. This type of stablecoins is centralized, due to having both a backing asset and third party involvement. The cost of maintaining the stability of the stablecoin is equivalent to the cost of maintaining the backing reserve and the cost of legal compliance, maintaining licenses, auditors and the business infrastructure required by the regulator. The main risk of stablecoins backed by fiat currencies is loss of value of the backing currency and the loss of trust into the centralized governance (issuer, custodian and auditors).
Exchange-traded commodities backed stablecoins
Stablecoins that are backed by exchange-traded commodities such as precious metals (gold, silver etc) are quite similar to fiat currency backed stablecoins. Their main characteristics are:
- Their value is pegged to an exchange-traded commodity in a fixed ratio,
- The peg is realized off-chain, through regulated financial institutions which serve as custodians of the commodity backing the stablecoin,
- The amount of exchange-traded commodity used to back the stablecoin has to reflect the circulating supply of the stablecoin.
The value of stablecoins backed by exchange-traded commodities relies on the value of the backing asset. Holders of exchange-traded commodities backed stablecoins can redeem their stablecoins at the conversion rate to take possession of real assets. This type of stablecoins is centralized, due to having both a backing asset and third party involvement. The cost of maintaining the stability of the stablecoin is equivalent to the cost of maintaining the backing reserve of the exchange-traded commodity and the cost of legal compliance, maintaining licenses, auditors and the business infrastructure required by the regulator. The main risk of stablecoins backed by exchange-traded commodieis is loss of value of the backing assets and the loss of trust into the centralized governance (issuer, custodian and auditors).
Examples: Digix Gold Tokens (DGX) and others.
Cryptocurrency backed stablecoins
Cryptocurrency backed stablecoins are issued with cryptocurrencies as collateral, which is conceptually similar to fiat-backed stablecoins. However, the significant difference between the two designs is that while fiat collateralization typically happens off-chain, the cryptocurrency or crypto asset used to back this type of stablecoins is done on-chain, using smart contracts in a more decentralized fashion. In many cases, these work by allowing users to take out a loan against a smart-contract via locking up collateral, making it more worthwhile to pay off their debt should the stablecoin ever decrease in value. To prevent sudden crashes, a user who takes out a loan may be liquidated by the smart contract should their collateral decrease too close to the value of their withdrawal.
Significant features of crypto-backed stablecoins are:
- The value of the stablecoin is collateralized by an another cryptocurrency or a cryptocurrency portfolio,
- The peg is executed on-chain via smart contracts,
- The supply of the stablecoins is regulated on-chain, using smart contracts,
- The price stability is achieved through introduction of supplementary instruments and incentives, not just the collateral.
The technical implementation of this type of stablecoins is more complex and varied than that of fiat-collateralized stablecoins, which introduces a greater risks of exploits due to bugs in the smart contract code. With the tethering done on-chain, it is not subject to third party regulation creating a decentralized solution. The potentially problematic aspect of this type of stablecoins is the change in value of the collateral and the reliance on supplementary instruments. The complexity and non-direct backing of the stablecoin may deter usage, as it may be difficult to comprehend how the price is actually ensured. Due to the nature of the highly volatile and convergent cryptocurrency market, a very large collateral must also be maintained to ensure the stability.
Live stablecoins projects of this type are Havven (the pair: nUSD - stablecoin and HAV - the collateral- backed nUSD), DAI (pair: CDP - Collateralized Debt Position and MKR - governance token used to control the supply) and others.
Seigniorage (algorithmic) stablecoins
Stablecoins can be linked to a DAO which controls issuance and pricing, which are referred to as seigniorage-style (or algorithmic) stablecoins. These stablecoins are fully digitalized and non-reliant on any types of collateral, with their supply and target price are to be controlled only by the program code. This feature makes the fully decentralized with no third party regulation possibility and highly scalable as they don’t require additional collateralization when the supply increases.
Algorithmic stablecoins are characterized by:
- Full decentralization,
- High scalability,
- Peg is realized on-chain,
- Low cost of price stability, as they require no collaterals.
The supply of algorithmic stablecoins is typically controlled by issuing and destroying coins depending on the market demand, until the target price is reached. In the general case, market participants are incentivized to act in a way that the price is kept at target level by issuing either bonds, in times of decreasing price or seigniorage shares when the price is above target.
Tethered cryptocurrency assets
Tethered cryptocurrency assets have certain features of algorithmic stablecoins - and can be considered their sub-type, except they don’t offer incentives in form of separate instruments (bonds or shares) to holders of the “underlying” cryptocurrency and there is no governing algorithm that forces the price towards the target, except at the moment of creation of the asset.
Significant features of tethered cryptocurrency assets:
- Full decentralization,
- Collateralization is realized on-chain when creating tethered assets with a fixed value denominated in the chosen peg (which is spent by the issuer and is the creation cost) without locking additional assets,
- Peg is realized on-chain, based on consensus,
- Unlimited valuation scalability, growth scalability is limited by the market capitalization of the underlying cryptocurrency,
- Specific handling due to non-mandatory on-chain usage.
Tethered cryptocurrency assets are issued on-chain, by holders of the native cryptocurrency, with different pegs chosen by the issuer. The peg value is imported into the blockchain by consensus and can be a number of fiat currencies and exchange-traded commodities (e.g. USD, EUR, gold, silver, etc). The issuer selects the peg and issues the tethered asset by paying the proprietary amount in the native cryptocurrency. As the cryptocurrency supply is fixed, in order to maintain the market capitalization at the time of issuing the tethered asset, the amount of cryptocurrency used to issue the asset is redistributed to holders on pro-rata basis. A specific mechanism controls the supply of tethered assets at the moment of issuance: in case there are tethered assets offered for sale, the issuer will buy them at face value, while the process of creating new assets will be triggered only in cases when there are no tethered assets offered for sale. An additional feature is to be built in the wallet, that will allow holders of tethered assets to trade them for a discounted price, a well as to trade assets with different pegs (e.g. USD tethered assets for gold tethered assets).
The main risk of this type of stable-asset is the loss of value of the peg (as with any other pegged stablecoin) and the excess liquidity of tethered assets which may drive the price of e.g. USD tethered asset below its’ face value.
Tethered cryptocurrency assets with published implementation proposals are in pre-launch phase.
Tether, the largest stablecoin by market capitalization, has faced accusations of being unable to provide audits for their reserves while continually printing millions; many have attributed their unverifiable creation of new coins to Bitcoin's rise in price in 2017. Stablecoins can be prone to failure as well due to volatility and upkeep required in many cases; NuBits is one example of a stablecoin which has failed in keeping its peg.
- Memon, Bilal. "Guide to Stablecoin: Types of Stablecoins & Its Importance". Retrieved 22 Oct 2018.
- "Gold-Pegged Vs. USD-Pegged Cryptocurrencies". Investopedia. Retrieved 27 October 2018.
- Tether. "Tether: Fiat currencies on the Bitcoin blockchain" (PDF). Tether: Fiat currencies on the Bitcoin blockchain: 7. Retrieved 2018-10-23.
- Cascarilla, Charles (2018-09-09). "Paxos Standard White Paper" (PDF). Paxos Standard White Paper: 5.
- Centre (May 2018). "Centre Whitepaper" (PDF). Centre Whitepaper: 10.
- Gemini Trust Company, LLC. "The Gemini Dollar: A Regulated Stable Value Coin" (PDF). The Gemini Dollar: A Regulated Stable Value Coin: 2. Retrieved 2018-10-23.
- "Gold-Pegged Vs. USD-Pegged Cryptocurrencies". Investopedia. Retrieved 27 October 2018.
- Eufemio, Anthony C.; Chng, Kai C.; Djie, Shaun (Jul 2018). "Digix's Whitepaper: The Gold Standard in Crypto-Assets" (PDF). Digix’s Whitepaper: The Gold Standard in Crypto-Assets: 2.
- Brooks, Samuel; Jurisevic, Anton; Spain, Michael; Warwick, Kain (2018-06-11). "A decentralised payment network and stablecoin" (PDF). A decentralised payment network and stablecoin v0.8: 6–9.
- "The Dai Stablecoin System". Retrieved 2018-10-23.
- "Stablecoin". Investopedia. Retrieved 27 October 2018.
- Al-Naji, Nader; Chen, Josh; Diao, Lawrence (2017-06-20). "Basis: A Price-Stable Cryptocurrency with an Algorithmic Central Bank" (PDF). Basis: A Price-Stable Cryptocurrency with an Algorithmic Central Bank: 8–16.
- Kuo, Evan; Iles, Brandon. "Ampleforth - An Ideal Money". Ampleforth - An Ideal Money: 10–11.
- Glover, Eiland; Reitano, John W. "The Kowala Protocol: A Family of Distributed, Self-Regulating, Asset-Tracking Cryptocurrencies" (PDF). The Kowala Protocol: A Family of Distributed, Self-Regulating, Asset-Tracking Cryptocurrencies: 5–11.
- PoCC/rico666 (2018-07-16). "To-All Transactions".
- PoCC/rico666; PoCC/ac0v (2018-07-16). "Anchor Real-World Data in Blockchain".
- PoCC/rico666 (2018-07-16). "Tethered Assets".
- "'Without this bitcoin price would collapse'". NewsComAu. Retrieved 2018-06-11.
- "Stablecoin NuBits Loses $1 Peg, No Recovery in Sight - Chainstate". Chainstate. 2018-05-12. Retrieved 2018-06-11.