Morgan Stanley has lost a senior trader from its Japan equity business, Kiyoko Hashimoto, who headed up index trading at the firm for the last 10 years. She was an executive director with a 15 year tenure at the firm. It could not be determined whether she is headed to another firm and she could not be reached for comment. Jay Sapsford, spokesman in Tokyo, declined to comment on whether Hashimoto has been replaced and who she reported to.