Aluminium stocks held at three major Japanese ports stood at 470,200 tonnes at the end of April, up 2.9 percent from 457,000 tonnes a month earlier, trading house Marubeni Corp said on Friday. That broke the previous record set in March, the highest level in data going back nearly 15 years. Marubeni collects data from the ports of Yokohama, Nagoya and Osaka. April 2015 March 2015 April 2014 Yokohama 234,000MT 220,000MT 121,200MT Nagoya 221,200MT 220,500MT 111,100MT Osaka 15,000MT 16,500MT 15,000MT TOTAL 470,200MT 457,000MT 247,300MT