CAMBRIDGE – Manufacturing solutions maker ATS Automation Tooling Systems Inc. finalizes a $50-million offering of 10 million shares to a group of investors led by Toronto’s GMP Securities. The company’s principal shareholder, New York-based hedge fund Mason Capital Management, purchased two million shares and now controls 12% of the company’s stock. ATS recently sold the key operating assets and liabilities of its Precision Components Group business, composed of two Canadian operations and one in China, to a group led by PCG Management. Terms of the deal have not been released.