A group of U.S. credit unions looking to pool resources considered the Bitcoin and Ethereum blockchains to track their business, but wound up selecting something else entirely: hashgraph.

Hashgraph, like Bitcoin blockchain, is a distributed ledger, a decentralized online record of transactions that can be accessed by multiple parties. Once it launches a public ledger version, promoters say, hashgraph should be a faster, cheaper alternative to the blockchain, but the very features that can make the older system slower and costlier are also the ones that attracted investors in the first place.

Technologies such as hashgraph, and the similar IOTA and ByteBall, rely on "directed acyclic graphs" to track information. Hashgraph's DAG records information in a timed series so that the record of each transaction is dependent on the ordering of all the previous transactions in the series. In blockchain, only one record of a transaction exists. If two miners create blocks at the same time, the community will chose the one transaction to go with, and dump the other. In hashgraph, no transaction is discarded. There can be many branches to the transaction record, and they all can continue to grow until a consensus can be determined.