# Ethereum Block Builders: Market Share of Blocks

> Ethereum block builders ranked by share of blocks: builder concentration, MEV-Boost payments to validators and locally built blocks, read from every block.

Markdown copy of https://voltfincrypto.com/apps/ethereum-block-builders

**Question:** Which builders produce the most Ethereum blocks, and how concentrated is block building?

- Kind: Dashboard in Voltfin Vantage
- Topic: [Ethereum](https://voltfincrypto.com/topics/ethereum)
- Chains: Ethereum
- Status: Planned. The data is not published yet, so this page states no figure; each figure will open its receipt when it is.

Most Ethereum blocks are not assembled by the validator who proposes them. Through MEV-Boost, proposers sell the right to fill a block to specialized builders, who compete on how much they pay. This dashboard identifies the builder of every block from its extra data and fee recipient, and shows each builder's share of blocks, how concentrated building is and what proposers received.

Concentration matters because a few builders decide which transactions enter most blocks and in what order. Read the share chart for who builds and the concentration index for how evenly building is spread; the payment series shows what the auction is worth to validators. Each block's attribution names the field it came from, so it can be checked.

## Blueprint

### Market share

Who built recent blocks and how concentrated building is.

- **Largest builder's share** (%): Share of blocks in the selected period built by the builder with the most blocks.
- **Three largest builders' share** (%): Share of blocks in the period built by the three builders with the most blocks.
- **Concentration index** (index): Herfindahl-Hirschman index of builder shares of blocks in the period, from zero (spread out) to one (a single builder).
- **Locally built blocks** (%): Share of blocks in the period built by the proposer's own client, with no outside builder.
- **Builder share by day** (%): Each builder's share of blocks per day over the period, with locally built blocks as their own band.
- **Every builder**: Each builder with its blocks, share, median payment to proposers and the extra data and fee recipients that identify it.

### Payments

What builders paid proposers, by day and by builder.

- **Paid to proposers** (ETH): Total builders paid to proposers in the period, from each block's final payment.
- **Median payment per block** (ETH): Median payment to the proposer per builder-made block in the period.
- **Payments by day** (ETH): Builder payments to proposers per day, beside the priority fees proposers received directly.
- **Median payment by builder** (ETH): Median payment per block for each builder over the period, to show which builders bid the most for blocks.

Filters: Period (Last day, week, month or year).

## How it will be measured

- The builder of each block is identified from its extra_data and fee_recipient, matched against a reviewed registry of builder names and addresses.
- A block counts as built through MEV-Boost when it ends with a payment from the builder's fee recipient to the proposer's, or when the proposer is the fee recipient and a known builder signs the extra data.
- Blocks with neither are counted as built locally by the proposer's own client, whose extra data usually names the client software.
- Concentration is the Herfindahl-Hirschman index of builder shares, with the share of the largest builders beside it, over the selected period.
- Payments to proposers are read from those final transactions, or from the priority fees paid to the proposer's address when there is none; they are valued at the day's ETH/USD oracle price.

## Data it needs

- `mev_daily` (to build): Blocks by builder, MEV-Boost relay share, and detected sandwich attacks with the value taken from users, per day.
- `address_labels` (to build): Labels for known addresses: exchanges, bridges, protocols, funds, treasuries, sanctioned addresses and known attackers.
- `native_prices_daily` (to build): Reference prices of major assets read from on-chain oracle feeds (Chainlink latestRoundData) at each day's last block, with each round's update time.
- Source: Block headers: extra_data and fee_recipient of every block
- Source: The final transaction of each block, from the builder's fee recipient to the proposer's
- Source: Priority fees paid to each block's fee recipient, from receipts
- Source: A reviewed builder registry of extra data strings and fee recipient addresses
- Source: Chainlink ETH/USD at day-end blocks for USD values

## Questions

### What is a block builder?

A builder assembles a full block from public transactions and private bundles sent by searchers, ordering them to capture the most value. It bids for the right to have its block proposed, and the proposer takes the highest bid through MEV-Boost relays.

### How concentrated is Ethereum block building?

Block building has been concentrated among a few builders for most of its history, because the builders with the most order flow can bid the most. This dashboard measures concentration for any period with the Herfindahl-Hirschman index and the largest builders' share, so the answer comes with its dates.

### What is proposer-builder separation?

The split between the validator who proposes a block and the builder who fills it. Until it is enshrined, the split runs outside the protocol through MEV-Boost and relays; EIP-7732, planned for the Glamsterdam upgrade, moves it into the protocol.

### How much do builders pay validators?

It changes with the value in each block: busy markets and liquidations make blocks worth more. The dashboard reads each block's payment from its final transaction and shows the median and the total per day, in ETH and USD.

### What is a locally built block?

A block the proposer's own client assembled from the public mempool, without an outside builder. Some validators build locally on purpose; others fall back to it when relays fail or no bid clears the minimum they set.

## Glossary

- **Builder**: A party that assembles complete blocks and bids for proposers to propose them.
- **Relay**: A service that passes builders' blocks to proposers and keeps their contents hidden until the proposer commits to one.
- **Herfindahl-Hirschman index**: A measure of concentration: the sum of each participant's squared market share, higher when a few hold most of the market.
- **Order flow**: The transactions and bundles that reach a builder, privately or from the public mempool; more flow lets a builder bid more.

## Related apps

- [Sandwich Attack Checker: Was My Swap Front-Run?](https://voltfincrypto.com/apps/sandwich-attack-checker)
- [Ethereum Network Revenue: Daily Fees, Tips and Burn](https://voltfincrypto.com/apps/ethereum-network-revenue)
- [Next Ethereum Upgrade: Glamsterdam Status and Fork History](https://voltfincrypto.com/apps/next-ethereum-upgrade)
- [Ethereum Gas Limit Tracker: Block Gas Limit Over Time](https://voltfincrypto.com/apps/ethereum-gas-limit)
- [Ethereum Gas Tracker](https://voltfincrypto.com/apps/ethereum-gas-tracker)
- [ETH Supply Tracker: Burn vs Issuance](https://voltfincrypto.com/apps/eth-supply-burn-vs-issuance)

Build it in Voltfin Studio: https://app.voltfincrypto.com/signup?next=%2F