Kenneth C. Griffin, founder and CEO of US hedge fund firm Citadel, has raised his stake in Spanish renewable power and gas supplier Audax Renovables SA (<a href="https://www.bolsasymercados.es/bme-exchange/es/Mercados-y-Cotizaciones/Acciones/Mercado-Continuo/Ficha/Audax-Renovables-ES0136463017" target="_blank">BME:ADX</a>) to 3.039%, according to a filing sent to Spain’s stock market watchdog CNMV on Friday.