[ARFC] Add XAUt to Aave v3 Core Instance

[ARFC] Add XAUt to Aave v3 Core Instance

Author: ACI

Date: 2025-06-19

ARFC updated 2025-07-04


Summary

The proposal aims to onboard Tether’s XAUt gold-denominated stablecoin, to the Aave v3 Core Instance, after successful [TEMP CHECK] Add XAUt to Aave V3 Core Instance and TEMP CHECK Snapshot.

Motivation

XAUt is a gold backed digital currency offered by Tether.

XAUt represents a unique opportunity to bring gold-backed assets into DeFi lending markets. Adding XAUt to Aave v3 would:

  1. Diversify the protocol’s offerings with a historically stable store of value
  2. Enable users to use gold-backed tokens as collateral or for lending, creating new DeFi use cases
  3. Allow users a hedge against market volatility through exposure to physical gold
  4. Attract traditional finance users who are familiar with gold as an asset class

The addition of XAUt aligns with Aave’s goal of expanding DeFi accessibility while maintaining strong risk management practices through the use of established, well-backed assets.

Specification

Ticker: XAUt

Contract address:

Risk Parameters will be provided by Risk Services Providers at the earliest possible and ARFC will be updated with that feedback.

ARFC updated 2025-07-04

Parameter Value
Asset XAUt
Isolation Mode Yes
Borrowable No
Collateral Enabled Yes
Supply Cap 5,000
Borrow Cap -
Debt Ceiling $3,000,000
LTV 70%
LT 75%
Liquidation Penalty 6%
Liquidation Protocol Fee 10%
Variable Base -
Variable Slope1 -
Variable Slope2 -
Uoptimal -
Reserve Factor -
Stable Borrowing Disabled
Flashloanable Yes
Siloed Borrowing No
Borrowable in Isolation No
E-Mode Category N/A

Disclosure

ACI (Aave Chan Initiative) is not afiliated with Tether and has not received compensation for creating this proposal.

Next Steps

  1. Now - Publication of a standard ARFC, collect community & service providers feedback before escalating proposal to ARFC snapshot stage.
  2. If the ARFC snapshot outcome is YAE, publish an AIP vote for final confirmation and enforcement of the proposal.

Copyright

Copyright and related rights waived via CC0.

9 Likes

Borrow stables for gold as collateral makes gold very interesting again.
Gold contains the dollar interest rate, it’s the best option for lazy stable farmers.

Summary

LlamaRisk supports the onboarding of XAUt to the Aave V3 Ethereum Core instance. The asset poses limited risk to the protocol, with primary concerns stemming from the absence of a bug bounty program, lack of a timelock on contract upgrades, absence of public smart contract audits, and reliance on off-chain accounting infrastructure to secure the gold backing XAUt. A significant concentration of on-chain liquidity has emerged, with a single entity, Abraxas Capital Management, beginning to provide most of DEX liquidity on Ethereum just a week ago. This poses a potential risk of a liquidity crunch if the entity chooses to withdraw its liquidity in the future.

Gold reserve attestations are published quarterly, with the most recent report released on April 23, 2025, conducted by BDO Italia. Pricing the asset posed a unique challenge, as gold markets do not operate 24/7. To prevent unnecessary volatility during weekends, we recommend using Chainlink’s XAU/USD price feed, which reflects institutional gold pricing and remains static when markets close during weekends. Despite the above considerations, XAUt presents a low overall risk profile for integration into Aave markets.

Collateral Risk Assessment

1. Asset Fundamental Characteristics

1.1 Asset

XAU₮, branded as “Tether Gold,” is an ERC-20 tokenized representation of investment-grade physical gold. Each on-chain unit is linked to one troy fine ounce of London Good-Delivery bars stored in high-security vaults in Switzerland while the token circulates on the Ethereum mainnet. Although functionally a “stablecoin,” XAUt behaves more like a fully asset-collateralized commodity receipt: price tracks spot gold, supply expands only when new bars are deposited, and holders may redeem whole bars (≈430 oz) for delivery inside Switzerland. Bars are individually allocated; a public lookup tool shows the bar serial number, purity, and weight against each address, satisfying London Good-Delivery traceability standards.


Source: Tether Treasury Gold Mapping, Tether, June 21, 2025

1.2 Architecture

Tether Gold is issued by TG Commodities, S.A. de C.V., a Salvadoran corporation - an authorized Stable-Asset Issuer and an authorized Digital-Asset Service Provider under the supervision of the Comisión Nacional de Activos Digitales (CNAD), holding Registration Number PSAD-0032.

XAU₮ is natively deployed on Ethereum; supply on other networks is accessed through wrapped representations (for example, XAUt0 on TON). Each wrapper introduces additional bridge contract and custody risk on top of the issuer’s operational and regulatory exposures.


Source: Tether Gold Minting Infrastructure, LlamaRisk

Off-chain infrastructure is concentrated in Switzerland, where London Good-Delivery bars are held in high-security vaults. The issuer affirms that the bullion is fully insured but does not disclose policy limits or underwriting counterparts. Control of the smart-contract mint and burn functions rests with a TG Commodities multisig wallet; no external escrow agent or notary participates in key management.

Whoever controls the private keys of an Ethereum address can move the token, and that act of on-chain transfer is the only formality required to convey the beneficial interest in the ounce of gold that backs each unit. However, the legal title to the underlying bullion does not jump from vault to vault with every token movement. It sits with a professional custodian mandated by TG Commodities and remains there until a KYC-verified holder redeems at least one whole London Good-Delivery bar; only at that moment is the title re-assigned (or the bar liquidated for cash).

The token life cycle, as set out in the Relevant Information Document (RID) published by TG Commodities, proceeds through several discrete stages:
(1) AGCL, a Tether affiliate, acquires LBMA-standard bars on the Swiss spot market;
(2) title to those bars transfers to TG Commodities once the metal is lodged in the vault;
(3) TG Commodities mints exactly one XAU₮ for every fine troy ounce received and credits the tokens to AGCL;
(4) KYC-verified customers remit U.S. dollars to Tether Gold at Swiss spot price plus a 25 bp creation fee;
(5) TG Commodities moves the required tokens from AGCL’s inventory to the purchaser’s blockchain address;
(6) secondary holders may freely transfer, trade, or pledge XAU₮ without further intervention by the issuer;
(7) any holder with at least 430 XAU₮, approximately one standard London bar, may redeem for physical delivery in Switzerland or instruct liquidation for fiat, whereupon the redeemed tokens are permanently burned.

On-chain Issuance/Redemptions


Source: Tether Treasury XAUt Balance, Etherscan, June 21, 2025

The XAUt ERC-20 contract retains minting authority, though it has not been used in over three years. Instead, issuance and redemptions are handled off-chain by the Tether Treasury, which TG Commodities operate. This separation allows Tether to avoid minting new XAUt on demand and maintain a pre-minted, fully backed inventory for faster fulfillment. Currently, the treasury holds 59,645 XAUt out of the 246,524 tokens ever minted on Ethereum, a decline from its peak of 108,203 in March 2022, yet still representing a substantial 24.2% of the total supply. Notably, the treasury address is an externally owned account (EOA), not a smart contract, which means the entire accounting and issuance process occurs off-chain and remains unverifiable on-chain.

1.3 Tokenomics

Circulating supply mirrors the gold on deposit: every XAU₮ is minted only after an ounce of London Good-Delivery bullion is lodged in the Swiss vault and is burned on redemption. BDO Italia’s end-Q1 2025 attestation recorded 246,523.33 XAU₮ outstanding against the same number of fine ounces, about 7.7 tonnes of metal. The token has no hard cap; supply expands solely when TG Commodities acquires additional bars, so growth is driven by market demand rather than by any algorithmic mechanism.

Contractual convertibility into a specific ounce keeps secondary-market pricing tightly anchored to spot gold. Creation and redemption fees accrue entirely to TG Commodities, and storage and insurance costs are embedded in that spread. Because the token pays no yield, holders bear the opportunity cost of idle gold.

1.3.1 Token Holder Concentration


Source: Etherscan, June 20, 2025

The 10 largest Ethereum addresses jointly hold about 222,663 XAU₮ ≈ 90.3% of the supply. A single wallet alone (0x785…f7f6) controls more than 38 % of supply. Retail cohorts – addresses holding < 1 % of supply each – collectively own roughly 4 %.

The top 3 holders are:

  • 0x785…f7f6 - tagged by Arkham as an address operated by RhinoFi (formerly DeversiFi);
  • Tether Treasury - inventory under TG Commodities’ direct control, used for primary issuance and redemptions. Visible on-chain and referenced in Tether’s attestation.
  • 0xf9b3…8057 - un-labeled on Etherscan but moves in lock-step with Treasury; pattern suggests an internal omnibus or OTC settlement account.

Several next-largest wallets belong to centralized exchanges such as Bitfinex, Bybit, and Bitget or custodians such as Cobo Custody, indicating that a material portion of the float may sit in omnibus accounts.

2. Market Risk

2.1 Liquidity


Source: XAUt/USDC Swap Liquidity, DeFiLlama, June 20, 2025

Users can swap XAUt worth up to $9.44M (2800 XAUt) for USDC within a price impact of 6%.

2.1.1 Liquidity Venue Concentration


Source: Top XAUt Liquidity Pools on Ethereum by TVL, GeckoTerminal, June 20, 2025

The total XAUt liquidity across DEXs on Ethereum is approximately $16.5M. The primarly liquidity hubs are the Uniswap V3 XAUt/WBTC ($17.9M TVL), Uniswap V3 XAUt/USDT ($2.35M TVL), Uniswap V3 PAXG/XAUt ($1.83M TVL), Curve XAUt/PAXG ($1.1M TVL), Uniswap V4 PAXG/XAUt ($313.7K TVL), and Uniswap V4 XAUt/USDT ($284.2K TVL).

2.1.2 DEX LP Concentration

Though XAUt liquidity is evenly distributed among DEXs on Ethereum, there is significant LP concentration, with a few entities providing the majority of liquidity in some pools. Below is the breakdown (as of June 20, 2025):

2.2 Volatility


Source: XAUt to XAU Chart, TradingView, June 20, 2025

From the chart, it is evident that the secondary market price of XAUt on Ethereum has deviated from the gold spot price (XAU/USD) by more than ±1% on numerous occasions, often for prolonged periods throughout the year, including twice in the past month. However, as on-chain liquidity improves, the secondary market price on Ethereum is converging more closely with the true price of gold.

2.3 Exchanges


Source: XAUt CEX Markets, Coingecko, June 20, 2025

Tether Gold (XAUt) is actively traded across multiple centralized exchanges (CEXs), providing additional secondary market liquidity. This has enhanced the efficiency of DEX/CEX arbitrage. Approximately $2M worth of XAUt can be sold on CEXs with no more than 2% slippage.

2.4 Growth


Source: XAUt Circulating Supply on Ethereum, Dune, June 20, 2025

Since March 2023, the on-chain supply of XAUt on Ethereum has remained constant at 246,524 tokens. However, the share held by externally owned accounts (EOAs) has been steadily increasing, while the share held by centralized exchanges (CEXs) continues to decline. This shift in ownership suggests that more XAUt is now in the hands of users likely to deploy it into DeFi protocols, signaling growing readiness for on-chain utility.

3. Technological Risk

3.1 Smart Contract Risk

According to Tether, smart contract reviews are conducted at two levels. The first level ensures that operating procedures are consistent and accurate and that all issues are identified and resolved. The second involves testing in a live environment to ensure that only the admin can access privileged functions such as minting, freezing, and unfreezing. However, Tether has not publicly available any of these audits or reviews. BlockSec published a blog highlighting a public transfer vulnerability in the Tether Gold smart contract. This issue was patched following an upgrade to the proxy implementation of XAUt on May 25, 2023, making it plausible that BlockSec was involved in the fix.

3.2 Bug Bounty Program

XAUt’s smart contracts are not included in Tether’s existing $10,000 bug bounty program, which only covers the Tether.to and app.tether.to domains. While the contracts have been battle-tested over the years, the absence of a dedicated bug bounty program leaves risk mitigation incomplete.

3.3 Price Feed Risk

Pricing XAUt accurately presents certain challenges, as the London Bullion Market, which primarily influences its value, remains closed on weekends, and gold price fixing occurs only twice on weekdays at 10:30 and 15:00 UTC. Chainlink’s XAU/USD price feed, which reflects the institutional gold spot price, offers a viable solution for pricing XAUt on Ethereum. It helps mitigate unnecessary volatility risks over the weekend that would be introduced by a direct 24/7 XAUt/USD feed (currently unavailable). The feed is categorized as low market risk, with a deviation threshold of 0.3% and a heartbeat of 24 hours. Price stagnation over weekends does not pose a significant risk, as liquidations cannot be triggered while the oracle remains static, and the likelihood of bad debt is minimal due to gold’s inherently low volatility.

3.4 Dependency Risk

Off-chain Operational Infrastructure
The functionality of XAUt depends entirely on the centralized infrastructure operated by TG Commodities Limited, its issuer. The on-chain issuance of XAUt tokens is done via the Tether Treasury EOA, which is not a transparent smart contract. The entire XAUt system hinges on accurate reconciliation between off-chain gold reserves and on-chain token supply. This bridge connecting physical audits, vault balances, treasury inventories, and token distribution is not automated or verifiable via smart contract logic. Any failure, delay, or misreporting in this reconciliation process could lead to mismatches between circulating supply and actual reserves, eroding trust in the system.

London Bullion Market
XAUt does not aim to maintain a static peg; rather, it seeks to track the dynamic price of physical gold. This creates a direct dependency on the health, liquidity, and accessibility of the global gold markets, primarily the London Bullion Market Association (LBMA), which serves as the global standard for wholesale gold price discovery. The price at which the issuer processes redemptions and the price reported by oracles for use in DeFi protocols are derived from this market. The stable functioning of the market is also essential.

Custodial & Physical Asset Risks
XAUt’s value critically depends on its physical backing, introducing risk from the third-party custodian who vaults the gold. This includes potential theft, fraud, or damage to the reserves. The system’s integrity also relies on infrequent or potentially inaccurate third-party audits, insurance policies that may not cover all loss scenarios, and a secure supply chain to guarantee the gold’s quality and legitimate origin. A failure in any part of this physical chain undermines the token’s value.

4. Counterparty Risk

4.1 Governance and Regulatory Risk

The regulatory risk was discussed in detail during the TEMP CHECK stage. As there have been no material changes, that assessment remains applicable here.

4.2 Access Control Risk

4.2.1 Contract Modification Options

Here are the controlling wallets:

  • Tether Multisig: A 3/6 threshold multisig deployed using a custom MultiSigWallet contract.

The following contracts power the XAUt architecture:

No role-based access control mechanism is used for XAUt contracts, and the ERC-20 contract controlled by Tether Multisig is solely responsible for handling sensitive functions like mint, redeem, blacklist (addToBlockedList, destroyBlockedFunds, removeFromBlockedList), transfer, change allowance (permit, increaseAllowance, decreaseAllowance), and transfer ownership.

4.2.2 Timelock Duration and Function

Tether has not configured any timelock on XAUt contract upgrades. A timelock functionality for critical contract upgrades should be preferred to adhere to the standard risk practices.

4.2.3 Multisig Threshold / Signer identity

The 3/6 threshold multisig that controls XAUt is managed by Tether and also serves as the owner of the USDT contract on Ethereum.

Note: This assessment follows the LLR-Aave Framework, a comprehensive methodology for asset onboarding and parameterization in Aave V3. This framework is continuously updated and available here.

Aave V3 Specific Parameters

Parameters will be presented jointly with @ChaosLabs

Price feed Recommendation

Chainlink’s XAU/USD feed can be used to price XAUt on the Aave V3 Ethereum Core instance.

Disclaimer

This review was independently prepared by LlamaRisk, a community-led decentralized organization funded in part by the Aave DAO. LlamaRisk is not directly affiliated with the protocol(s) reviewed in this assessment and did not receive any compensation from the protocol(s) or their affiliated entities for this work.

The information provided should not be construed as legal, financial, tax, or professional advice.

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Following our assessment and recommendation for XAUt, we would like to provide the Aave DAO with additional context on the peculiarities of pricing this asset and on the considerations involved in selecting the preferred pricing method and setting the associated parameters (namely, conservative LT and LTV to maintain a sufficient buffer).

XAUt Pricing

Pricing XAUt accurately presents certain challenges, as the London Bullion Market, which primarily influences its value, remains closed on weekends, and gold price fixing occurs only twice on weekdays at 10:30 and 15:00 UTC.

Approach 1: Gold Primary Feed

Price feed: Chainlink XAU/USD

This feed reflects the institutional gold price and remains static on weekends. It helps mitigate unnecessary volatility over the weekends introduced by a secondary market XAUt feed.

Source: XAUt Secondary Market Price vs XAU Spot Price, TradingView, June 27, 2025

The chart above illustrates the price deviation between XAUt in the secondary market (Uniswap V3 XAUt/WBTC pool on Ethereum) and the gold spot price from the OANDA:XAUUSD feed. Note: OANDA is a forex and CFD broker, not a commodities exchange like COMEX or LBMA. Their XAU/USD feed is an indicative spot price, typically derived from global liquidity providers who aggregate institutional price quotes themselves.

The blue segments highlight weekend periods, where the Oracle feed remains static while the secondary market continues trading. Although weekend volatility is observable, the deviation has exceeded ±2% only once since the pool’s inception six months ago. Price discrepancies typically revert within a day or two after traditional markets reopen on Monday. The maximum observed deviation has been +2.19% and -2.96%.

We outline two weekend scenarios where Oracle price stagnation could introduce potential risks:

Upside Deviation

If XAUt’s price rises on secondary markets over the weekend while the Aave price feed remains static, the on-chain collateral valuation remains unchanged. This restricts borrowing capacity but does not introduce protocol risk, as undercollateralization cannot occur. No bad debt is possible from upward deviations during oracle inactivity.

Downside Deviation

In this scenario, XAUt trades below its oracle price over the weekend when the Aave oracle remains static due to closed traditional markets. This creates a potential arbitrage window where discounted XAUt can be acquired from secondary markets while Aave still values it at a higher price based on stale data. Bad debt can occur if the market anticipates a significant drop in the underlying gold price when trading resumes, causing the secondary market price of XAUt to dislocate in advance. If borrowers use this overvalued collateral to borrow stablecoins and the gold price indeed drops after markets reopen (and the oracle updates), the value of the collateral may fall below the borrowed amount, leading to bad debt if liquidation cannot happen in time.

Under the proposed parameters (LTV: 70%, LT: 75%), the protocol has a 26.6% buffer before bad debt becomes possible. This buffer is derived from the liquidation mechanics, including a 6% liquidation bonus (LB).

Importantly, gold has never experienced a daily price drop exceeding 26% in modern history, making this scenario statistically improbable. Moreover, because Aave’s oracle remains static during weekends, borrowers have time to monitor and adjust their positions before liquidation becomes possible once price feeds resume.

Approach 2: Dedicated Tether Gold Feed

A standalone Chainlink feed specifically for XAUt/USD would source real-time price data from CEXs and DEXs where XAUt is actively traded, such as OKX, Bitget, Bitfinex, and Uniswap. The combined DEX liquidity for XAUt on Ethereum is approximately $16.5 million, while an additional $8 million worth of XAUt can be sold on centralized exchanges with less than 2% price impact. While this feed would offer 24/7 price updates, it is important to note that XAUt is not listed on Tier 1 exchanges like Coinbase or Binance. As a result, price discovery may be less robust, and the 24/7 nature of this feed could introduce unnecessary weekend volatility and speculative noise into Aave markets.

Conclusion

Based on the current market conditions and Oracle design considerations, we recommend proceeding with the first option, which is using the existing Chainlink XAU/USD price feed with appropriate safeguards as the preferred approach for pricing XAUt. We will be presenting the proposed parameters jointly with @ChaosLabs.

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Overview

Chaos Labs supports listing XAUt on Aave’s Ethereum Core instance. Below is our analysis and initial risk parameter recommendations.

Technical Overview

XAUt, or Tether Gold Token, is a digital asset issued by TG Commodities S.A. de C.V., representing ownership of one fine troy ounce of physical gold per token. Each XAUt is fully backed by a uniquely identifiable gold bullion bar stored in a Swiss vault and meeting “London Good Delivery” standards set by the LBMA. Users verified through Tether Gold’s KYC process can purchase or redeem tokens via the primary market on Tether’s platform, with redemptions requiring full gold bar denominations.

A complete reserve report has been carried out by BDO Italia S.p.A., an independent member of the global BDO network and a licensed statutory audit firm in Italy. From the reserve report, we observe that the total gold held in reserve amounted to 246,524.380 fine troy ounces, while the XAUt tokens in circulation were 246,524.330000 XAUt, demonstrating a strict 1:1 asset backing with a marginal surplus of physical gold. This affirms that each token is fully collateralized by a corresponding fine troy ounce of gold securely vaulted. The market value of the reserves, as of 31 March 2025, was reported at $770,036,001, based on a valuation of USD 3,123.57 per ounce. The gold inventory, consisting of 644 bars, majorly 12.5 kg bars (611 units), is stored in Swiss vaults and conforms to the London Good Delivery standards set by the LBMA. Importantly, the inventory is not recognized as an asset of Tether, but rather constitutes the legally segregated property of XAUt token holders, thereby forming the physical foundation for all outstanding tokens.

Reserve Inventory Breakdown

Only users who complete the required KYC verification process are eligible to mint new XAUt tokens through the Primary Market, which operates via the Tether Gold Website. Tokens can only be minted after TG Commodities confirms that a corresponding quantity of physical gold has been deposited with the custodian and passed intake procedures. The minimum minting amount is 50 XAUt. A non-refundable verification fee of $150 is charged during the onboarding process; however, this fee is credited back upon successful KYC approval and can be applied toward future redemptions. There are no ongoing storage or custody fees. Redemptions are only allowed in full gold bar increments. Alternatively, KYC Verified Customers may opt for TG Commodities to sell the redeemed gold on their behalf in the Swiss market and receive fiat proceeds. Tether Gold does not support redemption or physical delivery for Secondary Market holders.

Legal Structure

XAUt are issued by TG Commodities, S.A. de C.V., a company incorporated and operating under the Laws of El Salvador. TG Commodities is a registered Stablecoin Issuer and Digital Assets Service Provider (DASP), duly authorized by El Salvador’s National Commission of Digital Assets (CNAD) with registration number PSAD–0032. The company is wholly owned by Tether Holdings, S.A. de C.V., and Tether Operations, S.A. de C.V., both incorporated in El Salvador. TG Commodities is a member of the Tether Group. The physical gold backing XAUt is vaulted in Switzerland and held by an affiliated but legally separate Swiss custodian, which operates independently of the Tether Group and maintains distinct financial accounts, personnel, and customer records. This structure ensures that the Gold Reserves are legally segregated assets owned by the token holders, not the issuer, and are not available to satisfy Tether’s own liabilities.


TG Commodities Legal Structure

TG Commodities’ issuance of XAUt is formally governed by El Salvador’s Law for the Issuance of Digital Assets and the Regulations on Public Offerings of Stablecoins, under which XAUt qualifies as a regulated stablecoin backed by an international reserve asset. Pursuant to Article 5 of the Stablecoin Regulations, TG Commodities submitted a complete Relevant Information Document (RID) and was granted authorization to issue stablecoins following the CNAD’s Resolution of No Objection. The RID discloses TG Commodities’ legal structure, shareholding, governance, minting/redemption rules, and physical gold inventory processes, in compliance with documentary requirements enumerated in the public-offering regime.

Market Cap & Liquidity

A total of 246,524.33 XAUt has been minted to date, resulting in a market cap of $822.55M. Of this amount, 186,879.51 XAUt is currently in circulation, distributed across 8,204 holders. The remaining 59,644.82 XAUt is held by Tether and remains in a ready-to-sell state.


XAUt Top Holder

XAUt has shown strong on-chain activity over the past six months, particularly in the past month, during which the average daily transfer amount exceeded 5K.


XAUt On-Chain Activity

XAUt’s onchain liquidity is primarily supported by three key pools. The largest is the WBTC/XAUt pool on Uniswap V3, with a TVL of $16.8M, followed by the XAUt/USDT pool, which holds $2.4M. In addition, there is a Curve pool for XAUt/PAXG with $1.27M in TVL.

In addition, we observed that the liquidity in the current two uniswap pools has only recently seen a significant increase, whereas prior to that, both maintained relatively low volumes. Upon further analysis, we found that before early 2025, some of the XAUt trading activity took place in a separate XAUt/USDT Uniswap V3 pool with a 0.05% fee tier. Below, we present the aggregated XAUt liquidity across these four pools over time.

Volatility

XAUt’s volatility is tightly correlated with the price of gold. In the past 30 days, XAUt exhibited a moderate uptick in volatility, reaching a daily annualized level of 16.95%.

Below is the historical price comparison between XAUt and XAU. The price of XAUt is derived from transaction data in the XAUt/USDT Uniswap liquidity pool, while the XAU price is sourced from the XAU Chainlink oracle. As shown in the chart, XAUt has generally tracked the market price of gold closely over the past year, in line with its one to one physical gold backing model. Nonetheless, occasional price dislocations have been observed.

These deviations are primarily driven by the structural difference between XAUt’s continuous trading on crypto exchanges and the limited operating hours of traditional gold markets. While physical gold does not trade on weekends, XAUt remains fully tradable around the clock. This mismatch can lead to temporary price gaps during off-market hours, when no real-time benchmark is available from the gold market. During such periods, XAUt may diverge from the spot price of gold, with the peg typically re-aligning once traditional markets reopen. As shown below, the largest recorded deviation we observed reached approximately 4.5%.

Another contributing factor to the observed deviations between the XAUt trading price in the Uniswap pool and the XAU Chainlink oracle is the historically low liquidity in the XAUt/USDT pools prior to 2025. In low-liquidity environments, even modest trades can result in price slippage, making arbitrage less profitable or even unviable after accounting for transaction costs. As a result, when temporary dislocations between XAUt and the underlying gold price occurred, there was limited incentive for arbitrageurs to correct the spread. However, as onchain liquidity for XAUt improved, especially after January 2025, we observed that the price deviations gradually became smaller.

LTV, Liquidation Threshold, and Liquidation Bonus

Although XAUt’s reserve structure ensures a 1:1 physical gold backing, which underpins its fundamental stability, the observed volatility, particularly during off-market hours, warrants a conservative risk parameter configuration. Specifically, we recommend setting the Liquidation Bonus at 6%, the LTV ratio at 70%, and the LT at 75%.

Supply Cap and Borrow Cap

Given XAUt’s current robust on-chain liquidity, alongside its significant liquidity on centralized exchanges, assigning a relatively high supply cap is reasonable. However, since the surge in on-chain liquidity has occurred only within the past month, leaving limited historical data, we recommend setting an initial supply cap of 5,000 XAUt. Chaos Labs will continue to monitor market conditions and user behavior to adjust the supply cap as needed in real time.

Based on our historical observations, XAUt, being a volatile asset, is most likely to be borrowed for shorting purposes. Therefore, we do not recommend enabling it as a borrowable asset at this time.

Oracle

We recommend utilizing the XAU oracle to price XAUt. Unlike physical gold, which trades during standard market hours, XAUt remains tradable 24/7. This structural difference often leads to price dislocations, particularly during weekends when gold markets are closed but XAUt continues to trade.

Using the XAU oracle also introduces safety properties for lending protocols. During upside deviations, where XAUt trades above the last published gold price, the oracle limits user borrowing capacity by anchoring to a more conservative value, effectively imposing a lower LTV ratio over the weekend. On the downside, significant divergence would require an abrupt and sustained decline in gold price, a historically rare event. Even in those cases, price reversion at market open typically restores the peg before any protocol-level risk is realized.

Isolation Mode and Debt Ceiling

Chaos Labs also recommends listing the asset in Isolation mode to prevent it from being used as collateral to borrow volatile assets. Significant price movements in the borrowed assets, combined with potential deviations between XAUt and XAU during off-market hours, could increase the risk of bad debt.

CAPO

We recommend using the XAU/USD oracle as the primary pricing source for XAUt. However, in anticipation of the future availability of a dedicated XAUt oracle alongside significant observed growth in the underlying asset, we may propose a stable CAPO adapter configuration that ensures XAUt pricing remains within a reasonable range anchored to the underlying gold market. The purpose of this CAPO is to safeguard against oracle returns that could deviate significantly to the upside from the spot price of gold during market hours, which may distort market behavior and lead to mispriced collateral values. Simultaneously, this structure would inherit any underlying exposure in the event of an adverse scenario occurring to Tether, akin to USDT. However, this previously described CAPO setup can introduce risks of downside price manipulation without the presence of sufficiently deep liquidity; for this reason, we recommend analysing the risks of this configuration in depth before its adoption.

Specification

Following the above analysis, we recommend the following parameter settings:

Parameter Value
Asset XAUt
Isolation Mode Yes
Borrowable No
Collateral Enabled Yes
Supply Cap 5,000
Borrow Cap -
Debt Ceiling $3,000,000
LTV 70%
LT 75%
Liquidation Penalty 6%
Liquidation Protocol Fee 10%
Variable Base -
Variable Slope1 -
Variable Slope2 -
Uoptimal -
Reserve Factor -
Stable Borrowing Disabled
Flashloanable Yes
Siloed Borrowing No
Borrowable in Isolation No
E-Mode Category N/A

Disclaimer

Chaos Labs has not been compensated by any third party for publishing this recommendation.

Copyright

Copyright and related rights waived via CC0

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What’s the status of this, is it still being considered for the ARFC vote?

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What is the ETA for this proposal? :eyes:

People are eager to use XAUt as collateral

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XAUt technical analysis


Summary


This is a technical analysis of all the smart contracts of the XAUt asset and its main dependencies.

Disclosure: This is not an exhaustive security review of the asset like the ones done by Tether, but an analysis from an Aave technical service provider on different aspects we consider critical to review before a new type of listing. Consequently, like with any security review, this is not an absolute statement that the asset is flawless, only that, in our opinion, we don’t see significant problems with its integration with Aave, apart from different trust points.

Analysis

Tether Gold (XAUt) is a tokenized representation of physical gold on the Ethereum blockchain. Tokens are minted once the corresponding physical gold bars, in the equivalent number of fine troy ounces, have passed the Custodian’s intake process. The reserves are held in Switzerland. Subject to KYC, customers can purchase XAUt directly from Tether with a minimum order of 50 XAUt (50 fine troy ounces). Redemptions are available only in whole-bar increments, and token holders can redeem the physical gold in Switzerland.


For the context of this analysis, our focus has been on the following aspects, critical for the correct and secure integration with Aave:

  • A recommendation of pricing strategy to be used in the integration asset <> Aave.
  • Any miscellaneous aspect of the code that can be considered important.
  • Analysis of the access control (ownerships, admin roles) and the nature of the entities involved in the system. Regarding the table permissions’ holders and their criticality/risk, it is done following these guidelines:
Criticality Description
CRITICAL Usually super-admin functionality: it can compromise the system by completely changing its fundamentals, leading to loss of funds if misused or exploited. E.g. proxy admin, default admin
HIGH It can control several parts of the system with some risk of losing funds. E.g., general owners or admin roles involved in the flow of funds
MEDIUM It can cause malfunction and/or minor financial losses if misused or exploited. E.g., fee setter, fee recipient addresses
LOW It can cause system malfunctions but on non-critical parts without meaningful/direct financial losses. E.g., updating descriptions or certain non-critical parameters.

Risk Description
:green_circle: The role is controlled via a mechanism we consider safe, such as on-chain governance, a timelock contract, or setups involving multi-sigs under certain circumstances.
:yellow_circle: The role is controlled in a way that could expose the system and users to some risk depending on the actions it can control.
:red_circle: The role is controlled via a clearly non-secure method, representing risks for the system and users.

General points

  • XAUt relies on a single contract with most dependencies from OZ for access control, tokenization, upgradability, and security. It uses the OZ Transparent Proxy pattern.
  • The system uses the ownable pattern for minting, burning tokens, and blocking addresses.
  • The system’s upgradable admin and the owner of XAUt is the Tether multisig 3-of-6.

Contracts

The following is a non-exhaustive overview of the main smart contracts involved with XAUt.


XAUt

The primary contract for the Tether gold tokenization system. XAUt is an upgradable OZ ERC20 with minting, burning, and blacklisting capabilities, which are managed via ownable access control. Customers can acquire XAUt directly with Tether after passing the KYC requirements. The contract is upgradable by the Tether multisig 3-of-6.

Permission Owner functions Criticality Risk
upgradable admin: Tether multisig 3-of-6 upgrade, upgradeAndCall CRITICAL :yellow_circle:
Owner: Tether multisig 3-of-6 mint, redeem, destroyBlockedFunds, addToBlockedList, removeFromBlockedList, transferOwnership HIGH :yellow_circle:

  • Access Control
    • The owner can mint new XAUt tokens by calling the mint(to, amount) function. Currently,
    • The owner can redeem his own XAUt tokens via the redeem(amount) function.
    • The owner can add or remove users in the blacklist via the addToBlockedList(address) removeFromBlockedList(address) methods.
    • The owner can burn funds from blacklist addresses via the destroyBlockedFunds(address) function.

Pricing strategy

Tether Gold is another example of a complex asset with multiple price options, each with its own pros and cons. Since it is a tokenized asset and its reserves are traded only during regular market hours, it remains an on-chain asset that can still be freely traded on weekends. With that said, we have two options:

  1. Chainlink XAU/USD feed:

    Refers to the institutional global gold price, which reflects the behavior of the real-world asset. However, it relies on a “stale” price during off-market hours when gold markets are closed, and XAUt still trades on CEX and DEXes, where it might be valued differently than the oracle indicates. This can cause price deviations that could potentially lead to bad debt if the price drops below market risk parameters when trading resumes.

  2. Chainlink XAUt/USD feed:

    Considers XAUt price aggregated from secondary markets and treats it solely as an on-chain asset. This approach exposes the asset on Aave to volatility during off-market hours and fails to account for its underlying nature. However, the low liquidity of secondary markets is susceptible to manipulation, which could lead to unnecessary liquidations.

Considering the asset’s nature, we recommend pricing XAUt using the XAU/USD Chainlink price feed; the first option appears reasonable and does not pose a significant risk of bad debt, given the conservative risk parameters suggested by the risk teams and gold’s long history of not dropping to substantial levels in a very short period.
Still, we highlight the importance of being very conservative on risk parameters, given the nature of the underlying, very different to any other listed on the protocol.


Miscellaneous

Conclusion

We believe XAUt has no issues with Aave integration and no major blockers for listing.
We consider XAUt’s upgradability without a timelock acceptable, but only due to a combination of factors: XAUt issued by Tether, its upgrades are governed by the same multisig as USDT, and Aave already operating USDT under the same setup. Still, we have recommended the Tether team to evaluate adding timelocking on upgradeability.

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The current proposal has been escalated to ARFC Snapshot.

Vote will start tomorrow, we encourage everyone to participate.

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After Snapshot monitoring, the current ARFC Snapshot recently ended, reaching out both Quorum and YAE as winning option with 890.7K votes.

Therefore, [ARFC] Add XAUt to Aave v3 Core Instance has PASSED.

Next step will be the publication of an AIP for final confirmation of the proposal.

Token is in, congrats !

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