Christian Schettling, a senior fixed income derivatives marketer to Germany at Lehman Brothers in London, has quit the firm and market buzz has connected him with a similar role at SG Corporate & Investment Banking. Schettling is on gardening leave and could not be reached, but officials familiar with the situation said he will report to David Ishoo-Mirzayoo, head of institutional fixed income derivatives marketing. Ishoo-Mirzayoo was traveling and could not be reached and spokeswoman Michelle Gathercole did not comment by press time.