"Citi has demonstrated a commitment to the custody business through their proprietary sub-custodian network and investment in technology, enabling them to deliver custody services in an integrated, efficient and transparent manner," Age Bakker, chief operating officer at NBIM, said in a statement released by Citigroup. Norway's sovereign wealth fund, which invests the country's oil wealth and held 1.3 percent of the world's listed stocks at the end of last year, purchases several services from external providers, such as investment managers. "The selection of a new global custodian supports our strategic goal to achieve the highest possible operational automation and efficiency in each market that we invest in to realize increased efficiencies and robustness in the Norges Bank Investment Management organization at a competitive cost," the fund said Monday. NBIM in September 2010 sued Citigroup over $835 million in losses in the bank's stock and bonds, claiming it misrepresented its financial condition and failed to disclose information as the fund bought securities at inflated prices between January 2007 and January 2009.