Fei Protocol Suffers Incentive Vulnerability — What Lies Ahead for Algorithmic Stablecoins

On April 7, the development team behind Fei Protocol, a novel algorithmic stablecoin project, announced that "due to a vulnerability in Fei's incentive calculation, all minting rewards for Fei will be suspended." One day later, the team announced the shutdown of the "burn mechanism" to address the previously discovered incentive vulnerability. The team stated that shutting down the "burn mechanism" would help reduce selling pressure and pull Fei back to its peg target.

Fei's Direct Incentive Mechanism

In our previous articles, we briefly introduced the two main design mechanisms currently used by algorithmic stablecoins — passive mechanisms and active mechanisms. A key improvement of the active mechanism is the introduction of more user behaviors,发行多种代币, incentivizing users to participate in token burning and minting. And Fei, the subject of today's discussion, employs an active mechanism.

As we know, unlike fiat-collateralized or crypto asset-collateralized stablecoins , if algorithmic stablecoins want to maintain their price at the pegged price over the long term, they necessarily need a complete set of rules to constrain participants' behavior, and the core of this system is rewards and penalties. Fei Protocol uses direct incentive measures to punish Trading that deviates from the pegged price, and reward Trading that moves toward the pegged price. In theory, this results in deflation, which helps adjust FEI's supply. This is precisely where the problem occurred this time.

(Fei Protocol's direct incentive model, source: Fei whitepaper)

The above is the incentive model — direct incentives — adopted by Fei Protocol to stabilize token price.

Let us explain by quoting a passage from the Fei Protocol whitepaper:

"Direct incentive stablecoins are currencies where both trading activity and stablecoin usage are incentivized, with rewards and penalties pulling the price toward the pegged price. Generally, there is at least one incentivized trading hub at the center, and all other trading venues and secondary markets can utilize this incentivized hub for arbitrage. This helps maintain the peg throughout the entire ecosystem."

Put simply, Fei Protocol achieves its stablecoin price target by incentivizing Uniswap trading volume through minting and burning. These incentive measures are applied directly to traders' balances and are proportional to the deviation from the pegged exchange rate, meaning larger sells result in larger burns. The protocol incentivizes traders through minting to restore the price to the pegged price. The formula used ensures that all fluctuations below the pegged rate are net deflationary. This helps reduce the supply to a level appropriate for current demand.

Now, here is the issue. The above process operates under the assumption that Fei Protocol is running normally. When the incentive mechanism has a vulnerability (the specifics of which will not be explored in detail here), Fei's price becomes difficult to peg to the target price according to the established rules. Therefore, the Fei Protocol development team suspended minting rewards and the burn mechanism within two days.

What Happened Before This

Let us rewind to 3:00 AM on April 4 (Beijing time), when Fei completed its 3-day genesis distribution. According to public data, the event raised 639,000 ETH and minted 1.3 billion Fei, bringing over $2.6 billion in liquidity to Uniswap. FEI's popularity exceeded most people's expectations, and it instantly became the largest algorithmic stablecoin project by scale.

(April 4, screenshot from a Twitter user, source: internet)

(Fei price and liquidity on April 9, source: info.uniswap.org/)

As the comparison above shows, within just 5 days, Fei's liquidity on Uniswap dropped from $2.61 billion to $1.21 billion, and Fei's price fell to $0.78, far below its pegged price of $1.00. Clearly, some investors exploited the token allocation rules during the genesis distribution phase for speculative purposes.

Indeed, according to the rules, participants who entered during the genesis phase could deposit ETH to receive Fei at a discounted price and receive additional governance token airdrops. This appeared to be an attractive opportunity, ultimately drawing over 17,000 unique addresses to participate in the event.

However, this discounted price came with conditions. The genesis Fei discount was only available if the total funds committed were below $250 million in ETH. As of the end of the genesis distribution, a total of $1.3 billion in ETH had been committed — meaning the discount was voided. Furthermore, these ETH were irreversibly transferred to the project's PCV contract address to establish the Uniswap liquidity pool.

According to data from duneanalytics.com, among the top 70 investors by committed amount, 15 had conducted pre-swap trades. The largest investor pre-swapped a total of 9,999 ETH , which, calculated at OKX 's ETH closing price that day, amounted to $20.7 million.

(ETH price, source: OKX)

As of now, most top-ranked investors have converted their TRIBE governance tokens into Fei. Only a few have successfully front-run the conversion into ETH, while the rest have been trapped inside the Fei fortress due to FEI Protocol's burn mechanism. They are currently waiting for Fei to return to above water before making further plans.

Here is a brief explanation of Fei Protocol's burn mechanism. Since the protocol's intent is to maintain price stability and encourage long-term holding by investors, the burn mechanism's penalties can be quite severe. When Fei's price deviates 10% from the pegged price, if a holder chooses to sell Fei, it can result in a burn ratio of up to 100% — meaning that if an investor tries to quickly sell FEI during heavy selling pressure, they may suffer severe burn penalties, down to being completely wiped out.

What Insights Does This Give Us?

The reason Fei Protocol was able to attract such massive capital during its genesis distribution is largely due to backing from prominent investors. It is reported that the Fei team has raised $19 million in funding from top-tier investment institutions including A16z, Coinbase Ventures, and Framework. However, from the current perspective, the glamour of capital does not seem to shine as brightly in the DeFi space as it did during the internet era. After all, in the DeFi world, everything is open, entrepreneurial barriers are greatly lowered, and the values of equality and freedom are amplified infinitely — this is a place that rewards capability and creativity.

Following this incident, some commentators have suggested that the Fei project is a disaster of excess capital. Both its supporters and critics have offered their views. Critics argue this was a failed experiment, with some even calling out "all ETH should be refunded."

Supporters have reaffirmed their confidence in the project. For example, Compound founder R. Leshner posted on Twitter: "I'm still bidding $0.70 — I'll buy all the FEI you can sell me."

At this point, this experiment may not yet have succeeded, but there is no need to rush to declare it a failure.

"The most crowded investment opportunity is never the best." But when the crowded bubble dissipates, what remains沉淀 for us is undoubtedly the most valuable part. And this is also the opportunity that every era's pioneers dare to lead with — and the unavoidable challenges they will face. The development of algorithmic stablecoins has only just begun, and we need to give it more patience and more time. For future financial experiments in society, we still look forward to the emergence of more such stars. Perhaps we have arrived at a turning point in history.

Disclaimer: digital assets Trading involves significant risk. This material should not be used as the basis for investment decisions, nor should it be interpreted as advice to engage in investment Trading. Please ensure you fully understand the risks involved and invest cautiously. The OKX Academy only provides information for reference and does not constitute any investment advice. All investment behavior by users is unrelated to this site.

Disclaimer

This article may contain product-related content that does not apply to your region. This article is only committed to providing general information and is not responsible for any factual errors or omissions. This article represents only the author's personal views and does not represent the views of OKX. This article is not intended to provide any advice, including but not limited to: (i) investment advice or investment recommendations; (ii) offers or solicitations to purchase, sell, or hold digital assets; or (iii) financial, accounting, legal, or tax advice. Holdings in digital assets (including stablecoins) involve high risk and may fluctuate significantly or even become worthless. You should carefully consider whether Trading or holding digital assets is suitable for you based on your financial situation. For questions about your specific circumstances, please consult your legal/tax/investment professional. The information in this article (including market data and statistical information, where applicable) is provided for general reference purposes only. Although we have taken all reasonable precautions in preparing this data and these charts, we assume no responsibility for any factual errors or omissions expressed herein. © 2025 OKX. This article may be reproduced or distributed in its entirety or in excerpts of 100 words or less, provided that such use is non-commercial. Any reproduction or distribution of the full article must prominently state: "This article is copyrighted © 2025 OKX, used with permission." Permitted excerpts must cite the article title and include attribution, for example "Article title, [author name (if applicable)], © 2025 OKX." Some content may have been generated or assisted by artificial intelligence (AI) tools. Derivative works or other uses of this article are not permitted.

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