SEOUL, Dec 3 (Reuters) - South Korea’s foreign exchange reserves jumped by the largest amount in more than 10 years in November, Bank of Korea data showed on Thursday. The Bank of Korea held FX reserves of $436.38 billion at the end of November, a record high, up $9.87 billion from October - the biggest monthly increase since July 2010. The central bank attributed the rise to gains from management and the increase in the value of the overall reserves when converted into the dollar. In November, FX authorities repeatedly said they stood ready to take steps to stabilize currency markets as the won gained against the dollar, which many local currency dealers interpreted as authorities buying dollars to steady the market and in turn increase FX reserves. (Reporting by Cynthia Kim; Editing by Andrew Heavens)