1. Centralized stablecoins
    Currency backed stablecoins  Exchange-traded commodities backed stablecoins 

2. Decentralized stablecoins
    Cryptocurrency backed stablecoins 

3. Criticisms

4. Failed and abandoned stablecoin projects

5. References

Centralized stablecoins

Asset backed cryptocurrencies are by definition centralised since a controlling centralised body must manage the tangible physical asset.{{Citation needed|date=December 2018}}

Advantages of asset backed cryptocurrencies are that coins are stabilized by assets that fluctuate outside of the cryptocurrency space, that is, the underlying asset is not correlated, reducing financial risk. Bitcoin and altcoins are highly correlated, so that cryptocurrency holders cannot escape widespread price falls without exiting the market or taking refuge in asset backed stablecoins. Furthermore, such coins, assuming they are managed in good faith, and have a mechanism for redeeming the asset/s backing them, are unlikely to drop below the value of the underlying physical asset, due to arbitrage.

The main disadvantage and criticism levelled at centralised stablecoins is that they counter the decentralized, trustless ethos that has been crucial to the popularity and adoption of cryptocurrencies.

Centralized stablecoins are subject to the same volatility and risk associated with the backing asset. They are also exposed to loss of confidence in the centralized governance (issuer, custodian and auditors).^[2]

Centralised stablecoins can be divided into fiat-backed and commodities-backed stablecoins:

Currency backed stablecoins

Cryptocurrencies backed by currency are the most common and were the first type of stablecoins on the market. Their characteristics are:

• Their value is pegged to one or more currencies (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.

The value of stablecoins of this type is based on the value of the backing currency, which is held by a third-party regulated financial entity. In this setting, the trust in 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. 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.

Examples: TrueUSD (TUSD)^[1], USD Tether (USDT),^[3] Paxos Standard (PAX),^[4] Centre,^[5] Gemini Dollar (GUSD)^[6], Bitcoin Air (USDAP) and others.

Exchange-traded commodities backed stablecoins

Stablecoins backed by commodities such as precious metals (gold, silver etc) are quite similar to fiat backed stablecoins. Their main characteristics are:

• Their value is pegged to one or more exchange-traded commodities, 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.

Holders of commodity-backed stablecoins can redeem their stablecoins at the conversion rate to take possession of real assets. 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.

Examples: Digix Gold Tokens (DGX)^[7] and others.

Decentralized stablecoins

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 the blockchain, the cryptocurrency or crypto asset used to back this type of stablecoins is done on the blockchain, 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{{snd}} stablecoin and HAV{{snd}} the collateral-backed nUSD),^[8] DAI (pair: CDP{{snd}} Collateralized Debt Position and MKR{{snd}} governance token used to control the supply)^[9] and others.

Criticisms

Failed and abandoned stablecoin projects

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 to maintain its peg.^[11]

The stablecoin project Basis, which had received over $100 million in venture capital funding, shut down in December 2018, citing concerns about US regulation.^[12]

References

• Kristjan Makke
• Kristjan Moller
• Kristjan Niels Julius
• Kristjan Ragnarsson
• Kristjan sigurdsson
• Kristjansson
• Kristjan THor Juliusson
• Kristjan T. Ragnarsson
• Kristjan Trossmann
• Kristjan Valdimar Bjornson
• Kristján Einar
• Kristján Gudmundsson
• Kristján Karlsson
• Kristján Möller
• Kristjánsson
• Kristján Örn Sigurdsson
• Kristleifur Bjornsson
• Kristleifur Björnsson
• Kristmemelis
• Kristnihald undir Joekli
• Kristnihald undir Jokli
• Kristo (1996 film)
• Kristof
• Kristof Barati
• Kristofer Andreas Lange