Chinese regulators on Friday approved the sale of HSBC's remaining $7.5 billion stake in Ping An Insurance to a group controlled by Thai billionaire Dhanin Chearavanont. The sale of the stake in the country' no. 2 insurer marks China's largest inbound acquisition. HSBC, Europe's biggest bank, is trying to divest what it considers non-core assets to improve profits. It will book a $2.6 billion post-tax gain from the sale.