Private transactions now consume more than 50% of all Ethereum L1 gas, according to data from Blocknative's Data Archive. While these transactions represent roughly 30% of total transaction count, their disproportionate gas consumption — driven by complex DeFi swaps and MEV-sensitive operations —...
"You generally wait longer for a private transaction to get on-chain and therefore, you may suffer worse settlement due to increased slippage." — Matt Cutler, CEO & Co-Founder, Blocknative
Private transactions now consume more than 50% of all Ethereum L1 gas, according to data from Blocknative's Data Archive. While these transactions represent roughly 30% of total transaction count, their disproportionate gas consumption — driven by complex DeFi swaps and MEV-sensitive operations — marks what Blocknative calls "the flippening" in Ethereum's order flow structure. The top three block builders control 91–92% of all MEV-Boost blocks, with Titan Builder alone producing approximately 52% as of early April 2026.
The shift is not confined to Ethereum. On Solana, proprietary AMM "dark pools" such as HumidiFi now handle 35% of all DEX volume, processing $8.55 billion in a single week. Polygon launched a native Private Mempool on April 2, 2026. SOL Strategies acquired zero-knowledge privacy startup Darklake Labs on April 7 for $1.2 million. Across all major chains, transaction flow is migrating from public mempools to private, encrypted, or proprietary channels — creating measurably better execution for users while concentrating power among fewer intermediaries.
Blocknative's analysis of Ethereum L1 data shows private transactions grew from approximately 2% to over 15% of all transactions in a six-month period during 2023–2024, before crossing the 50% threshold of gas consumption by August 2024. That figure has remained above 50% since.
The dynamic is structural, not cyclical. Users conducting complex on-chain actions — multi-hop swaps, large-lot trades, liquidations — tend to route through private channels to avoid frontrunning and sandwich attacks. These operations are inherently gas-intensive. A single private swap may consume 10–50x the gas of a simple ETH transfer, which explains how 30% of transactions can account for more than half the gas.
Gas consumption attributed to private orders among the top four block builders — Titan, Beaver, Rsync, and Flashbots — grew 130–150% during the first half of 2024 alone, according to Blocknative:
Of these, approximately 45% of private transactions in mid-2024 were sent through MEV Blocker (CoW Protocol's order flow auction system), indicating that user-initiated MEV protection — not just builder-driven dark pools — is driving adoption.
The aggregate cost of MEV extraction on Ethereum since 2020 exceeds $1.8 billion, according to Shutter Network's analysis. Searchers extracted approximately $24 million in a single 30-day period between late 2025 and early 2026.
The growth of private order flow has produced a concentrated builder market. According to data from Rated Network and Relayscan as of early April 2026:
| Builder | Block Share | |---------|------------| | Titan Builder | ~52.16% | | BuilderNet (Flashbots) | ~24.63% | | Quasar | ~15.06% | | All others combined | ~8.15% |
MEV-Boost blocks account for approximately 90% of all Ethereum blocks. The top three builders produce 91–92% of those blocks. This means roughly 82–83% of all Ethereum blocks are produced by three entities.
The concentration is self-reinforcing. Private order flow providers impose reputation requirements on builders, typically evaluated by market share. New entrants must subsidize bids — up to 1.4 ETH per entry attempt — to win auctions and build track records. The result is what researchers at Decentralized Thoughts describe as a "chicken-and-egg" problem: builders need private order flow to profit, but only receive it if they already hold market share.
Ethereum's Glamsterdam upgrade, targeted for mid-2026, introduces enshrined Proposer-Builder Separation (ePBS), moving the block auction on-chain. This eliminates the relay layer but does not directly address order flow concentration. Vitalik Buterin's post-Glamsterdam roadmap includes FOCIL (Fork-Choice enforced Inclusion Lists) and encrypted mempools as subsequent steps, per the Hegotá upgrade planned for late 2026.
Solana's MEV infrastructure is dominated by a single actor: Jito Labs. Over 95% of Solana's active stake is delegated to validators running the Jito-Solana client. Jito's tip-based auction system has become the primary mechanism for transaction ordering on the network.
The numbers are substantial. Solana's Real Economic Value (REV) — transaction fees plus out-of-protocol MEV tips — reached an all-time high of $1.4 billion over the trailing year through late 2024. Jito tips alone accounted for roughly half of Solana's December 2024 REV, and in some periods, nearly two-thirds of total fee revenue came from Jito bundle tips.
One estimate pegs Solana MEV extraction at approximately $1.5 billion annually, as part of a broader $5 billion ecosystem of value extracted off-chain (including trading bots and pump-and-dump schemes), according to Bitget research. This figure is considered a lower bound.
A parallel development on Solana is the rise of proprietary AMM dark pools. HumidiFi, launched in May 2025, processed nearly $100 billion in cumulative trading volume in under five months, capturing approximately 35% of Solana's total DEX activity, according to DefiLlama. On a single day in September 2025, HumidiFi processed $1.92 billion in trades.
HumidiFi operates as a closed-loop system: it does not rely on public liquidity pools or user deposits. All trades route through aggregators like Jupiter (which processes over 80% of Solana swap volume). Blockworks Research data shows that proprietary AMMs — HumidiFi, SolFi, ZeroFi, and GoonFi — now account for nearly 50% of all SOL-stablecoin trading volume.
SOL Strategies' acquisition of Darklake Labs on April 7, 2026, for $1.2 million (payable primarily in shares) signals institutional interest in Solana privacy infrastructure. Darklake's Zyga system is a zero-knowledge proof engine that plugs into Solana's transaction-execution pipeline, hiding order details from arbitrageurs while allowing validators to verify correctness via zk-proofs. SOL Strategies, which holds 533,040 SOL (~$43.9 million as of April 1), described the acquisition as enabling "MEV-resistant, institution-ready Solana infrastructure."
Polygon launched its Private Mempool on April 2, 2026, offering a different architectural approach. Transactions submitted through the endpoint go directly to elected block producers, bypassing the public mempool entirely. Integration requires swapping a single RPC URL — no infrastructure changes.
The system relies on Polygon's VeBloP (Verifiable Block Production) architecture, where a known set of producers handles block creation while validators retain authority to replace them. This differs from Ethereum's competitive builder auction: Polygon's producers are permissioned but removable.
Polygon positions this as particularly relevant for institutional use cases. The chain processes more than $2.3 trillion in cumulative stablecoin volume, with integrations from Stripe, Revolut, Apollo, Flutterwave, and Reliance Jio. For cross-border payments, treasury management, and tokenized asset operations, predictable transaction ordering is a hard requirement.
The Private Mempool launches with a free tier, with enterprise tiers offering higher throughput and SLAs. Polygon's roadmap includes confidential payments, dedicated blockspace, and stable fees as next steps.
The distinction between "private" and "encrypted" mempools is non-trivial. Private mempools (Flashbots Protect, MEV Blocker, Polygon's Private Mempool) route transactions to a trusted set of builders or producers who can see transaction contents but commit not to exploit them. Encrypted mempools render transaction contents unreadable to all parties until ordering is finalized.
Shutter Network operates the only live encrypted mempool deployment, running on Gnosis Chain mainnet. The system uses threshold encryption: decryption keys are split across a committee of keyholders, and no single party can decipher a transaction alone. A threshold number of committee members must cooperate to reveal transaction contents after block ordering is fixed.
Shutter and Primev announced in December 2025 a partnership to bring the first threshold-encrypted mempool to Ethereum's PBS pathway. Separately, Shutter published EIP-8105 (Universal Enshrined Encrypted Mempool) in December 2025, proposing native encrypted mempool support in the Ethereum protocol. The EIP is technology-agnostic — it supports threshold encryption, multi-party computation, TEEs, delay schemes, and FHE — and is being proposed for inclusion in the Hegotá upgrade.
Aptos Labs proposed its own native Encrypted Mempool in October 2025, framing it as a prerequisite for institutional adoption: "Encrypted Mempool secures intent at the protocol layer and makes it safe for large values to move freely without fear of censorship or frontrunning."
Limitations remain. Shutter's Gnosis deployment currently averages approximately three minutes to inclusion (versus Gnosis's five-second block time), caused by limited adoption among validators and keyholders. a16z crypto has raised theoretical concerns: users may outsource encryption to wallet providers, who then hold plaintext access — reintroducing the trust assumption that encryption was supposed to eliminate.
The European Securities and Markets Authority (ESMA) published supervisory guidelines in 2025 under the EU's Markets in Crypto-Assets Regulation (MiCA) that explicitly reference MEV as an emerging risk to market integrity. The guidelines, based on Article 92(3) of MiCA, direct national competent authorities to "proactively identify and address potential and emerging risks, including behaviours unique to crypto markets like maximal extractable value (MEV) strategies."
This is the first time a major financial regulator has formally categorized MEV within a market abuse supervision framework. The guidelines adopt a risk-based approach, directing higher oversight toward entities posing greater risks — including "large trading platforms, brokers, validators, and influential individuals."
Whether MEV constitutes market manipulation under MiCA's definitions remains untested. The guidelines establish a monitoring framework, not an enforcement precedent. However, the regulatory signal is clear: private order flow, builder concentration, and MEV extraction are on the supervisory radar in the EU's €1.5+ trillion crypto market.
The migration to private order flow produces measurable improvements in user outcomes. Sandwich attacks — where a bot places orders before and after a user's trade to extract value — are structurally impossible when the transaction is invisible. Flashbots' MEV-Share protocol returns up to 90% of backrunning value to users.
However, the concentration costs are real:
Base fee volatility: Blocknative's data shows a linear correlation between private gas usage and base fee volatility on Ethereum L1. As more gas-intensive transactions move off the public mempool, remaining public transactions face less predictable pricing.
Builder oligopoly: Three entities control 82–83% of Ethereum block production. This concentration creates single points of failure and potential censorship vectors.
Transparency erosion: Pre-trade transparency — the ability for market participants to observe pending transactions — decreases as flow moves private. This may benefit individual users while degrading systemic price discovery.
Value redistribution: On Solana, MEV tips now rival or exceed base transaction fees as a source of validator income. This means network security funding increasingly depends on MEV extraction rather than protocol-level fees — a dependency that introduces volatility risk to the security budget.
Flashbots' BuilderNet (running on TEEs and sharing MEV with the community) and Rollup-Boost (extending the model to L2s, with Unichain as the first deployment) represent attempts to retain the execution-quality benefits of private order flow while distributing the concentration risk.
The blockchain industry is undergoing a structural shift in how transactions reach blocks. Across Ethereum, Solana, and Polygon, the public mempool — once the default path for every transaction — is becoming a minority channel for economically significant activity. The data is unambiguous: users, wallets, and applications are routing through private channels at increasing rates, driven by the measurable cost of MEV exposure.
The economic logic is sound at the individual level. Users who route privately avoid sandwich attacks and frontrunning. Protocols that offer MEV protection attract more flow. Builders who control private order flow win more blocks.
The systemic implications are less straightforward. Builder concentration on Ethereum has reached levels where three entities produce the vast majority of blocks. On Solana, a single protocol's tip system generates more revenue than base transaction fees. These are not theoretical concerns — they are observable in on-chain data today.
The next phase — encrypted mempools, protocol-enshrined MEV protection, and regulatory oversight under MiCA — will determine whether the industry achieves MEV protection without centralizing block production. The technical proposals exist. The economic incentives to adopt them are present. Whether implementation matches ambition remains an open question.