At a time when Chinese companies are becoming increasingly confident about investing overseas, Aluminium Corporation of China’s acquisition of a 12 per cent stake in mining giant Rio Tinto is the boldest move yet.

Not only is it one of the biggest ever dawn raids of stock in a listed company and not only is Chinalco, as the group is known, breaking into one of the most prominent global M&A battles, but the $14bn investment is also the largest ever overseas purchase by a Chinese company – by nearly three times.