US-based heavy machinery maker Caterpillar Inc said its Chinese subsidiaries have signed three MOUs with the Shanghai Lingang Economic Development Co, an industrial park developer affiliated with Shanghai's municipal government. Caterpillar and Lingang will work to create a "regulatory system" that facilitates trade and investment in the region, a remanufacturing site and a service center. In a related development, China's leading machinery maker, Xugong Machinery, said last month Caterpillar was negotiating to buy a controlling stake in its construction machinery unit. Caterpillar's annual China sales is almost US$1 billion.