Kathryn Murphy has joined RBS Securities from Lehman Brothers. Murphy will focus on both primary and secondary loan sales out of New York and reports to Art de Peña, head of loan sales at RBS. Murphy, who spent seven years at Lehman, is joining as a v.p. on the loan sales and trading desk. In recent months, the firm has also hired Andrew Rothstein as a senior v.p. from Merrill Lynch Capital and Chad Hersch as an assistant v.p. from Credit Suisse First Boston.