The Gondola Group has sold restaurant chains ASK Italian and Zizzi to private equity firm Bridgepoint for £250m.
Zizzi has 136 restaurants across the country, while ASK has 109.
Steve Holmes, the chief executive of both businesses will remain with the brands, as will chief financial officer Jim Pickworth.
Harvey Smyth, chief executive of the Gondola Group, said: "ASK and Zizzi have made significant progress over the last few years. Both brands have strong positions in the UK casual dining market and exciting prospects for the future. The teams across ASK and Zizzi continue to do a fantastic job and they leave Gondola with our thanks and best wishes for the future.
Following the sale of Byron in November 2013 and PizzaExpress in August 2014, the sale of Ask and Zizzi is the last transaction in the break up of Gondola Group.
Steve Holmes, CEO of ASK and Zizzi, added: "We are delighted by the acquisition of ASK and Zizzi by Bridgepoint. This is a very exciting time for the business as we look to continue our strong trading momentum and further develop our footprint in the UK. We are looking forward to working with Bridgepoint to fulfil our ambitious growth plans."