Michimasa Naka got his start in the banking industry at Salomon Brothers in the foreign bond sales department. Four years later he was promoted to Vice President, and in 1999 he became Managing Director of Fixed Income at the brand new Nikko Salomon Smith Barney Ltd. where he managed foreign bonds, life insurance, and trust sales. He was promoted yet again in 2000 to Managing Director.  
Naka spent the next twelve years at Citigroup where he honed his experience in global markets. In his dozen years of experience he was a member of the Global Markets Asia Management Committee, a member of the Global Investor Sales Management Committee, Head of Global Markets Sales Japan, and the Deputy President of Citigroup Global Markets Japan. He oversaw Citigroup Global's fixed income and equity trading operations.   
Since 2010 Naka has served as the founder and chairman of independent securities firm, Stormharbour.