The woes in structured finance and mortgages are clearly leading to a changing of the guard as firms look to retool their capital markets oeprations; the latest evidence comes in the form of another Merrill Lynch & Co. (MER) addition, and the latest subtraction at Lehman Brothers Holdings Inc. (LEH). Lehman, whose fortunes have waned significantly in recent weeks as concerns over burgeoning U.S. mortgage exposure have grown, saw the head of its mortgage unit resign Thursday afternoon. Ted Janulis, global head of mortgage capital, will step down next month, the Wall Street Journal reported Friday morning. News of Janulis' departure comes as another executive, Rich McKinney, head of securitized products, also has left the firm; in McKinney's case, however, the departure is likely less about Lehman and much more about the death of securitization in general. Janulis has been named as a possible successor to current Freddie Mac (FRE) CEO Richard Syron, although no word on the soon-to-be-ex-Lehman execs post-departure plans has been made public. He's also the latest executive to leave Lehman in what appears to be an exodus at the top, of sorts. (FWIW, joining Freddie after leaving Lehman would have to be described as a textbook case of "out of the frying pan, and into the fryer." Freddie's woes as of late have been of the historic, global-economy-moving variety.) And over at Merrill, the mortgage build-up continues; Citigroup Inc. (C) has lost its top mortgage trader to the firm, the latest proof of a retooling over at Citigroup as CEO Vikram Pandit looks to turn around the ailing financial giant. reported late Thursday that lead mortgage trader Jim De Mare has left Citigroup to join Merrill, citing sources close to the company. De Mare is Merrill's second mortgage poach this month, with Bloomberg reporting on Aug. 8 that JP Morgan Chase & Co's (JPM) head of mortgage trading, Mike Nierenberg, recently quit and jumped ship over to Merrill as well. Sources tell HW that Merrill is eying the RMBS and related securities markets on three fronts: disposing of distressed assets, trading in the expanding agency securities space, and possibly looking to trade in distressed paper once that high-yield market begins to move. Our sources suggest that Street expectations for trading in that "junk bond" space is likely to pick up in the middle of next year. Disclosure: The author held no positions in companies mentioned when this story was published; indirect holdings may exist via mutual fund investments, as well. HW reporters and writers follow a strict disclosure policy, the first in the mortgage trade.