Owner families of South Korea\'s 10 largest conglomerates have seen the value of their stakes in listed affiliates grow more than two-fold over the last four years, data showed Thursday. Owner families\' stakes were valued at 50.7 trillion won (US$47.1 billion) as of end-April, compared with 20.4 trillion won in the same month in 2007, according to the data by the Korea Exchange (KRX).