When Barclays bought some the the assets of Lehman Brothers  - principally its U.S. operations - in September 2008, Ian Lowitt landed with Barclays and served as chief operating officer (COO) for the Barclays Wealth Management unit.  Lowitt, who left that position in April 2012, was the last CFO (chief financial officer) of Lehman Brothers when the firm filed for bankruptcy. On Thursday, it was announced that Mr. Lowitt, 48, has joined the London financial firm, Marex Spectron.  He will become that firm’s CFO and also act as head of global strategy, according to a release from the company.  Unlike Lehman, Marex is not a household name.  The company is privately owned and its Web site says it is "the world’s largest privately owned broker of financial products in the commodities sector and a leader in brokering physical energy products." Marex Spectron was acquired in 2010 by a PE firm started by Jeremy Isaacs, who had been Lehman’s CEO for Europe, the Middle East and Asia-Pacific. [C-I Note: It's always reassuring to see former associates looking out for each other.]   [Dealbook, 5/31/12]