Three credit derivative sales officials covering Iberia at Morgan Stanley in London have left the firm. Alvaro Pernas, head of structured product sales to the region, Gracia Lopez-Granados, structured sales, and Manuel Muniz Morell, flow sales, all resigned last Friday. Pernas, reached on his cell, said the three departures were not connected. Lopez-Granados did not return messages left on her cell and Muniz Morell could not be reached. Pernas said he has left to set up his own company, declining comment on the nature of the business. It could not be determined if Lopez-Granados and Muniz Morell have taken new positions elsewhere. All three staffers reported to Rob Rooney, European head of credit sales, who declined comment. Carlos Melville, spokesman, did not comment on replacements by press time.