Brian Murphy, formerly a whole loan mortgage-backed securities trader at Credit Suisse First Boston, left the firm earlier this month, according to individuals familiar with his move. Murphy was on vacation in Greece last week and could not be reached. He is expected to join Nomura Securities International in a few weeks and rejoin Brett Marvin, who is now head of adjustable-rate mortgages trading at Nomura, according to the individuals. Marvin, who recently joined from CSFB (BW, 4/5), said Murphy is not currently an employee of Nomura and declined to comment further.