Reading a sandwich

Graduate · enrolled learners

This lesson opens with The jaredfromsubway.eth sandwich bot, 2023.

What happened

Through 2023 a single Ethereum address, jaredfromsubway.eth, ran one of the most prolific sandwich operations on record, at times the largest gas spender on the network, and extracted on the order of tens of millions of dollars by sandwiching ordinary traders. Each attack is the same readable shape in a single block: the bot sees a victim's pending swap that will move a token's price, places its own buy of that token immediately before the victim (front-run), lets the victim's trade push the price up, and places its own sell immediately after (back-run), pocketing the difference the victim's own trade created. The victim receives worse execution, their slippage, and the bot keeps it. None of this is hidden; the three transactions sit in order in the block, on the same token pair, from the same bot address around the same victim, and reading that pattern is reading a sandwich.

The decision point

A sandwich is the most common and most legible MEV extraction, and learning to read one teaches the whole method of MEV analysis. The pattern is fixed: three transactions in a single block, a bot buy, a victim trade, a bot sell, all on the same token pair, with the bot's transactions bracketing the victim's. Once you see the shape you can measure it: the bot's profit is what it sold for minus what it bought for, and that profit is exactly the extra cost the victim paid in slippage, so a sandwich is a direct transfer from the trader to the ordering-privileged bot. jaredfromsubway.eth is the case at industrial scale, one address, the same three-transaction shape repeated relentlessly, tens of millions extracted, every instance sitting openly in the block for anyone who reads order rather than membership.

Recorded loss

$40,000,000

Orientation and Year One are open: anyone can read them without an account. From Year Two onward the lessons are for enrolled learners, because progress through the later years only means anything if it is tracked against a record.

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