LONDON, Dec 16 (Reuters) - Marieke Flament, chief executive of NatWest"s digital bank for businesses, is leaving after two and a half years to join Swiss-based blockchain foundation NEAR as CEO, she told Reuters. The non-profit NEAR oversees the governance and development of its blockchain of the same name, which it says makes it easier for entrepreneurs and developers to build financial products, non fungible tokens (NFTs) and other products. There is exploding global interest in digital assets, with NFT artworks selling for millions of dollars, but also rising scepticism about the sustainability of the boom and practical use cases for the underlying blockchain technology. Flament is leaving NatWest"s business bank Mettle, one of the British lender"s few remaining standalone digital bank initiatives, after it closed similar projects in recent years. NatWest in May 2020 shuttered Mettle"s equivalent for individual customers, Bó, after it attracted just 11,000 users since its launch in November 2019. In March this year it closed its online small business lending platform Esme Loans. "We have worked to ensure a smooth and orderly transition of Marieke’s responsibilities to Andrew Ellis, who is currently running Mettle in addition to his responsibility for our overall Ventures portfolio,” a spokesperson for the bank said. Mettle in 2021 has seen a fourfold increase in customer numbers and 1 billion pounds in customer transactions, the spokesperson told Reuters. Prior to NatWest Flament worked as European managing director at Circle, a platform allowing individuals and institutions to trade and make payments using cryptocurrencies. Flament will join NEAR on Jan. 1, she told Reuters, with a mandate to drive growth. The foundation is backed by venture capital funds including a16z, Pantera Capital, and Electric Capital.