NEM (New Economy Movement) is a Layer 1 blockchain launched on 31 March 2015, originally forked from the NXT codebase. It was among the earliest platforms to ship a native asset layer without smart contracts, introducing mosaics (user-defined tokens), namespaces (on-chain domain registration), multisignature accounts, and encrypted peer-to-peer messaging. Its client software, NIS (NEM Infrastructure Server), is written in Java and communicates via a RESTful API, making it straightforward to integrate without running a full node locally. At launch, NEM was notable for targeting enterprise and government adoption rather than open permissionless DeFi, and it found particular traction in Japan, where it powered payments and loyalty programmes.

NEM defining technical contribution is Proof-of-Importance (PoI), a consensus mechanism designed to reward genuine network participation rather than raw stake size. PoI scores are calculated from a combination of vested XEM holdings, transaction frequency, and transaction partners, using a variant of the EigenTrust++ algorithm. This design aimed to distribute block rewards more equitably than pure Proof-of-Stake and discourage passive coin hoarding. The maximum and circulating supply of XEM is fixed at 9 billion tokens, all of which were distributed at genesis, meaning no new XEM is ever created. NEM also introduced supernode rewards, paying high-performance nodes an XEM bounty from a dedicated fund to incentivise reliable infrastructure.

In January 2018, NEM became the subject of one of the largest exchange hacks in crypto history when the Japanese exchange Coincheck lost approximately 523 million XEM, valued at roughly $530 million at the time, due to funds being held in a hot wallet without multisig protection. The incident underscored the importance of the multisig features NEM had built but that Coincheck had not used. From 2019, the NEM Foundation restructured and development shifted toward a next-generation protocol. In March 2021 the Symbol mainnet launched as a sibling network with its own token, XYM, incorporating an updated architecture with aggregate transactions and enhanced mosaic functionality. The original NEM chain, now referred to as NIS1, remains operational and XEM continues to trade, but active development is concentrated on Symbol.