> For the complete documentation index, see [llms.txt](https://docs.comb.financial/utopia/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.comb.financial/utopia/features/capital-efficiency/maximum-extractable-value-mev/mev-on-existing-yield-optimizers.md).

# MEV on existing Yield Optimizers

Every yield aggregator found in the space typically go through the same process: harvest rewards, swap using one DEX, and compound that capital into more liquidity tokens.

<figure><img src="https://1447204207-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FVGZEcP2jzjD6Uja2Mlt5%2Fuploads%2FVQc8VcRtzqp6gsdhieJD%2Fimage.png?alt=media&amp;token=fe469e80-ad92-4c69-94b6-6ec3c73f9533" alt=""><figcaption></figcaption></figure>

Although this route is straightforward, there remains one issue—MEV. In this scenario, we can derive two opportunities in which MEV can extract value from the yield optimizer.

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The first opportunity would be a sandwich attack. Given that a yield optimizer does not protect its slippage (which many do not), a sandwich attack may be used to inflate the price of a token a block before the harvest and sell the token again at a higher price point.

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The second opportunity would be arbitrage. Given that liquidity isn’t sufficient, the effects of a harvest may incur a price impact, large enough to open arbitrage. Arbitrage is the act of balancing out liquidity across pools. For example, if the price of a token is significantly higher on DEX A than DEX B, the user can buy the token on DEX B to sell on DEX A to balance out the price, profiting from the difference in price.