NEM (New Economy Movement) is a blockchain-based platform for operation of mission-critical transactions for businesses. The platform has its own blockchain and a native token called XEM. NEM appeared on the market in 2015. Currently, it is one of the most successful blockchain projects hailing from Japan.
The NEM blockchain is permission-based. Stakeholders (who should have at least 10,000 XEM) participate in building of blocks ("harvesting"). The hierarchy of validators is based on the original proof-of-importance algorithm. It considers number of staked coins, volume of transactions, and other factors. Validation of transactions brings rewards for the stakeholders.
The level of security is OK, no issues so far.
NEM has always been my fav. Glad it still stays in top-100.
Stil believe in XEM