Maria Del Mar De Fez Laso, a fund derivative official at BNP Paribas in London, has left the firm. Julia Wilks, head of U.K. fund derivatives, declined comment. Stephane Liot, global head of fund derivatives in Paris, said she will be replaced, declining further comment. De Fez Laso's title could not be determined by press time, but officials close to BNP Paribas noted she had worked there close to three years after a previous role at Dresdner Kleinwort Wasserstein.