SoftBank Group Corp (9984.T) said it had led a $1 billion investment in U.S. financial technology startup SoFi, calling it the largest single financing round in the fintech space to date. The deal is the latest in the sector, where relatively young companies offer financial services through software. In July, Spain’s Banco Santander SA (SAN.MC) agreed to provide up to around $16 million for any opportunities it identifies with British mobile banking software partner Monitise Plc (MONI.L).