Flex doubles valuation to $1.2B in 6 months as $70M Series B1 backs global private banking push for middle-market owners Flex, an AI-driven private bank for high-net-worth business owners, raised $70 million in a Series B1 round, doubling its valuation to $1.2 billion in six months. The funding will support Flex's global expansion into private banking for middle-market owners. Flex, an AI-driven private bank for high-net-worth business owners, has raised $70 million in a Series B1 round…