Blake Grossman will become the sole CEO of Barclays Global Investors, part of a wave of management changes at Barclays PLC. Andrew Skirton, co-CEO of BGI who is based in London, will leave the firm, said Tom Taggart, a BGI spokesman. Messrs. Grossman and Skirton were named co-CEOs in June 2002, when Patricia C. Dunn, global CEO of BGI, stepped down for personal reasons. Mr. Grossman will continue to report to Robert E. Diamond Jr., president of parent Barclays PLC. "It was determined at the time of Ms. Dunn's departure that a dual CEO structure was the best model. Now we believe that BGI would benefit from a more simplified leadership and reporting structure," Mr. Taggart said. he said he did not know Mr. Skirton's plans.