Goldman Sachs' cohead of global fixed income, currency, and commodities sales, Dalinc Ariburnu, is leaving the bank, according to an internal memo seen by Business Insider. Ariburnu, 46, "decided to retire from the firm," according to the note, which was signed by the securities division coheads Isabelle Ealet, Pablo Salame, and Ashok Varadhan. Jim Esposito, who was recently promoted to chief strategy officer of the securities division, will replace Ariburnu while also continuing in his current role, according to a separate memo. The other cohead is Tom Cornacchia. "We continue to focus on critical initiatives ... (full story)