National Australia Bank has sold half of one of its few Chinese investments, the Financial Review reports.NAB sold an 8.42 per cent shareholding in China Industrial International Trust (CIIT) for 420.8 million yuan (A$82.5 million).China Industrial Bank, the trust's major shareholder, disclosed the sale. Fujian Energy Group was the buyer of the NAB stake.NAB has never disclosed the purchase price, but it was thought to have paid around $50 million for its 20 per cent stake in 2007, the AFR reports, speculating that NAB has more than doubled its money or made about $115 million in profit from the investment over the last decade, plus any dividends.