KEY TAKEAWAYS
- Bundled buys combine multiple token swaps into a single atomic execution, allowing block explorers to display related transactions as grouped entries.
- Sandwich attacks extracted approximately $60 million from Ethereum traders between November 2024 and October 2025, according to Cointelegraph Research based on EigenPhi data.
- Spam bots consume over 50% of gas on major OP Stack rollups while contributing less than 10% of total network fees, raising concerns about blockchain efficiency.
- Private transaction services, including Flashbots Protect and MEV Blocker, now handle approximately 80% of Ethereum DeFi interactions, helping traders reduce exposure to MEV attacks.
- Ethereum has recorded at least $1.3 billion in cumulative MEV extraction since 2020, with estimates ranging significantly higher depending on methodology.
Grouped entries on block explorers often confuse traders who expect one transaction per line. These clustered records are bundled buys, a method that packages several token swaps into one atomic execution.
Bundled transactions emerged alongside Flashbots in 2021 as a tool for validators and searchers. The system lets participants submit grouped orders that either execute together or fail. Between November 2024 and October 2025, over 95,000 sandwich attacks used this method, EigenPhi data showed.
This article breaks down how bundled buys work on chains, and explains what traders see on block explorers and how bots profit.
How Bundled Transactions Appear on Block Explorers
A standard Ethereum transaction appears as one entry with a single hash. Bundled buys look different because several operations share the same block position. Block explorers like Etherscan display these grouped entries under a single block number with sequential transaction indices.
The Flashbots system introduced this bundling mechanism through its modified MEV Geth client. Searchers submit transaction bundles directly to cooperating validators instead of broadcasting publicly.
Within months of launch, over 80% of Ethereum miners were processing bundles, a Flashbots transparency report from the pre-Merge era confirmed. After Ethereum’s transition to proof-of-stake, the equivalent metric shifted to validator adoption of MEV-Boost, which now stands at approximately 92%
Robert Miller, Flashbots product lead, noted that the update lets validators include several bundles in a single block. Bundles execute atomically, meaning all transactions land together or none do. A losing bundle never reaches the chain, so the searcher pays no gas for it.
This atomic property distinguishes bundled buys from regular multi-transaction activity. Traders reading block explorers can identify bundles by their sequential positioning and shared block inclusion. The key signal is multiple transactions from the same address occupying consecutive slots.
Why MEV Bots Rely on Bundled Transaction Strategies
Maximal Extractable Value (MEV) bots use bundled transactions to execute complex strategies atomically. The most common strategy is the sandwich attack, where bots place trades before and after a target swap. This front-run and back-run combination captures value from the price movement between trades.
EigenPhi data covering November 2024 to October 2025 tracked over 95,000 sandwich attacks on Ethereum. Monthly extraction fell from nearly $10 million in late 2024 to about $2.5 million by October 2025. About 70% of all sandwich attacks were linked to one operator known as jaredfromsubway.eth.
That bot had extracted roughly 117,000 ETH since March 2023, totaling approximately $295 million, KuCoin reporting confirmed. In June 2026, an attacker exploited the bot’s automated logic and drained approximately $7.5 million from its contracts, illustrating that even dominant MEV operators carry significant smart-contract risk.
Philip Daian, Flashbots steward, stated at Devcon that the organization aims to “use MEV as this decentralized engine in the long term,” according to Blockworks coverage. Bundled transactions remain the primary execution vehicle for this vision across the MEV supply chain.
Network Impact and the Scalability Cost of Bundled Bot Activity
Bundled bot activity now threatens blockchain scalability beyond Ethereum mainnet. A June 2025 Flashbots report found that spam bots consume more than 50% of gas on leading OP Stack rollups while paying under 10% of total fees.
On Base, two bots account for over 80% of spam transactions, the report detailed. Between November 2024 and February 2025, Base added 11 million gas per second of throughput. Flashbots noted that almost all of that new capacity was consumed by spam bots immediately.
Robert Miller of Flashbots wrote that “spectacularly wasteful on-chain searching is starting to consume most of the capacity of most high throughput blockchains,” according to a June 2025 post. He described the situation as “a market failure we can no longer ignore” in the same announcement.
Meanwhile, about 92% of Ethereum validators run MEV Boost, per Flashbots data, which adds an estimated 30% to 40% to base staking yield. A small number of block builders, including Titan, Beaverbuild, and Rsync, produce the majority of all MEV-boosted blocks, concentrating significant ordering power.
What’s Next?
Flashbots has proposed replacing gas-based bidding with a two part design using trusted execution environments. This system would let searchers submit off-chain bids while concealing user flows from frontrunning.
The approach could free most congested capacity, lower fees, and restore room for new applications. Ongoing research from CoW DAO and other MEV protection services continues to shape how bundled transactions evolve.
FAQs
What are bundled buys in cryptocurrency trading contexts?
Bundled buys are grouped transactions submitted atomically to blockchain validators, ensuring all included swaps execute together in one block or none execute at all.
How do bundled transactions appear on block explorers?
Block explorers display bundled transactions as sequential entries sharing the same block number, often from one address occupying consecutive transaction index positions within the block.
Why do MEV bots use bundled transactions?
MEV bots use bundles to guarantee atomic execution of multi-step strategies like sandwich attacks, eliminating gas costs from failed transactions that never reach the chain.
How much value have MEV bots extracted from Ethereum?
Cumulative Ethereum MEV extraction exceeds $1.3 billion since 2020 through mid-2026, with estimates varying by methodology.
What is a sandwich attack in decentralized trading?
A sandwich attack places a buy transaction before and a sell transaction after a target swap, capturing profit from the price movement that the victim trade creates.
Can traders protect themselves from bundled MEV attacks?
Private transaction routing through Flashbots Protect or MEV Blocker hides pending swaps from bots, with roughly 80% of DeFi interactions now using these protection services.
What role does Flashbots play in bundled transactions?
Flashbots created the bundle submission system through MEV Geth, enabling searchers to send grouped transactions directly to validators rather than broadcasting through the public mempool.
References
- Cointelegraph Research “Exclusive data from EigenPhi reveals that sandwich attacks on Ethereum have waned” (December 2025)
- The Block “MEV bots are clogging blockchains faster than networks can scale, says Flashbots” (June 2025)
- Vinyas & Janicot “Private MEV Protection RPCs: Benchmark Study” CoW DAO (May 2025)
- KuCoin News “JaredfromSubway.eth’s Sandwich Bot Extracts $295M” (August 2026)
