Nissan Motor Company on Friday said that it had increased its stake in a truck-making joint venture in China to 30 percent to expand market share in the country's booming commercial vehicle market, Associated Press (AP) reported. Citing Nissan spokesman Yuichi Nakagawa, AP said that the company last month purchased a 25-percent stake in the Zhengzhou Nissan joint venture from Sammitr Motors Co. of Thailand for an undisclosed amount.