South Korean lenders are tightening access to unsecured borrowing as concern grows over surging household debt, with internet-only banks joining a pullback that started with major commercial lenders. K Bank went furthest among online lenders, suspending all new overdraft accounts through July 31, the company said Tuesday. It has also capped daily credit loan applications and plans to lower limits for high-income borrowers. Kakao Bank, the country's largest internet-only bank, said it will cut th