The post-hard-fork DAO redemption contract. Still holds 81,716 ETH from token holders who never converted their DAO tokens back to ETH.
Historical Significance
The receipt of the largest hard fork in cryptocurrency history. The Ethereum community's decision to fork in response to the DAO hack on 17 June 2016 split the chain into Ethereum and Ethereum Classic and rewrote the foundational expectations about what 'code is law' meant. WithdrawDAO is the on-chain artefact of that decision: the contract that let everyone affected by the hack get their ETH back, and the contract that still holds the unclaimed 71 percent of those refunds a decade later. As the single largest dead-contract treasury on Ethereum (~330M USD at typical 2026 prices), it is also a permanent reminder of how much money disappears into the long tail of forgotten keys and abandoned wallets.
Context
Deployed 14 July 2016 at block 1,883,496, six days before the Ethereum hard fork at block 1,920,000 on 20 July 2016. The DAO had launched on 30 April 2016, raised 12.7 million ETH in its crowdsale (roughly 14 percent of all ETH in circulation at the time), and was drained of ~3.6 million ETH by an attacker exploiting a recursive-call vulnerability on 17 June 2016. The community spent five weeks debating a hard fork, with Vitalik Buterin and Vlad Zamfir publicly supporting a fork and the future Ethereum Classic camp opposing it. The fork passed, the funds were returned, and WithdrawDAO became the redemption rail. Solidity was at v0.3.5, the transferFrom(from, to, value) argument order had finally settled on the modern form, and throw was still the only error mechanism.
Key Facts
Description
WithdrawDAO is the contract that allowed holders of DAO tokens to convert them back to ETH at the rate of 1 ETH per 100 DAO tokens after the Ethereum hard fork of 20 July 2016. Deployed 14 July 2016 by 0x2ef1f605af5d03874ee88773f41c1382ac71c239, six days before the fork, at the same block height that the DAO hard-fork transition logic activated. It is the single most important post-fork contract in Ethereum's history.
The code is fifteen lines of pre-EIP-20-syntax Solidity. The constant mainDAO points at The DAO contract (0xbb9bc244d798123fde783fcc1c72d3bb8c189413). The trustee is hardcoded to 0xda4a4626d3e16e094de3225a751aab7128e96526. The withdraw() function takes the caller's DAO-token balance, transfers it into this contract, and sends back the equivalent ETH. The trusteeWithdraw() function lets the trustee sweep any residual ETH that exceeds totalSupply (typically zero unless dust accumulates).
Nearly a decade after deployment the contract still holds 81,716 ETH (worth ~330 million dollars at typical 2026 prices). That ETH belongs to DAO token holders who never claimed their refund. Wallet keys lost, exchanges that delisted DAO tokens, holders who never followed the hard-fork instructions: every uncollected DAO token corresponds to ETH still locked here. Roughly 71 percent of the original DAO token supply was never redeemed.
Compiled with Solidity v0.3.5+commit.48238c9 (1 July 2016), no optimizer. Source published by the Ethereum Foundation at deployment and verified on Etherscan.
Source Verified
Author-published source by the Ethereum Foundation team. Verified on Etherscan. The contract is fifteen lines of code, fully audited and well known.
Heuristic Analysis
The following characteristics were detected through bytecode analysis and may not be accurate.
Homestead Era
The first planned hard fork. Removed the canary contract, adjusted gas costs.
Bytecode Overview
Verified Source Available
Source verified on Etherscan.
View Verification ProofShow source code (Solidity)
contract DAO {
function balanceOf(address addr) returns (uint);
function transferFrom(address from, address to, uint balance) returns (bool);
uint public totalSupply;
}
contract WithdrawDAO {
DAO constant public mainDAO = DAO(0xbb9bc244d798123fde783fcc1c72d3bb8c189413);
address public trustee = 0xda4a4626d3e16e094de3225a751aab7128e96526;
function withdraw(){
uint balance = mainDAO.balanceOf(msg.sender);
if (!mainDAO.transferFrom(msg.sender, this, balance) || !msg.sender.send(balance))
throw;
}
function trusteeWithdraw() {
trustee.send((this.balance + mainDAO.balanceOf(this)) - mainDAO.totalSupply());
}
}