Charles Macintosh, mortgage-backed securities trader at Lehman Brothers, has left the firm and is believed to be headed to Merrill Lynch. At Lehman, he traded agency adjustable-rate mortgages and is expected to work in a similar role at Merrill. A Lehman official confirmed Macintosh's departure but declined further comment. Macintosh did not return an email message and could not be reached by press time. Terez Hanhan, Merrill spokeswoman could not provide further details by press time.