Citigroup, the world's largest bank by market cap, is understood to have applied to list its shares on the Tokyo Stock Exchange in the latest indication of its growth plans in Japan, the world's second-largest economy. According to a report in the Wall Street Journal, the New York-based bank filed with the exchange for an initial public offering several weeks ago. Details, including the date of a potential listing and the size of the deal, have yet to be decided. Earlier this year, Citigroup paid $10 billion to acquire the country's third-largest brokerage, Nikko Cordial. It has also adopted a holding-company structure in Japan, allowing it to acquire companies more easily here. In addition, Citigroup has received a Japanese domestic-banking licence, letting it open branches more easily. Previously it was licensed as a foreign bank, a status requiring it to get a separate licence for each branch. Citigroup hopes to attract Japan's savers and wants to use its Japanese branch network to sell mutual funds and alternative investments that it has access to because of its operations around the world. A listing in Japan will also give Citigroup stock it can swap for Japanese companies it might wish to buy in the future. Though the bank hasn't announced any plans to look for targets, Citigroup's expansion around the world has been fueled in part through acquisitions. Several international banks are currently upping their capacity in Japan. HSBC last week said it would launch a network of branches in January that would target more affluent customers. Other banks, such as UBS and Société Générale, are focusing on wealthy Japanese through private-banking offices in select cities.