A hack of The Dao resulted in the theft of approximately USD 50 million worth of Ether cryptocurrency.

The hack resulted from a critical vulnerability in The DAO’s smart contract code, allowing an attacker to manipulate the code and drain a substantial amount of Ether from The DAO’s funds. 

The vulnerability was reportedly related to the mechanism of splitting, which allowed token holders to exit the organisation and retrieve their Ether. 

Controversially, The DAO theft prompted Ethereum to do a so-called 'hard fork', in which the Ethereum network split into two as a way to restore the stolen funds.

Launched in April 2016, The DAO was an automated quasi-venture capital investment fund with no known management structure based on a digital decentralised autonomous organisation (DAO) that operated on the Ethereum blockchain, as built by German company Slock.it. 

The DAO raised USD 150 million in what was then the largest crowdfunding campaign, and was seen by enthusiasts as a revolutionary way to manage organisations of all kinds.

The incident raised questions about the governance and security of The DAO. 

It also sparked debate about the regulation of entities such as The DAO, as well as about the governance of decentralised autonomous organisations as a whole.