Samsung Electronics reported third-quarter earnings on Thursday. (Corrects period in paragraph 2 to July-to-September, not July-to-October) SEOUL, Oct 29 (Reuters) - Samsung Electronics said on Thursday its operating profit rose nearly ninefold to a record high. South Korea's KOSPI fell more than 2 percent to the 6,600 level as foreigners and institutions sold heavily. The index closed down 177.97 points, or 2.62 percent, at 6,625.93 after briefly rising.