Mining companies are an investment banker’s best friend. Since the start of 2007, Rio Tinto has paid out $174m in M&A fees. But recently it has also announced billions of dollars in writedowns, raising the question of whether the advice was worth the money?

Before 2007, Rio Tinto had not made a major acquisition since 2001, and its share price more than doubled over that period. It then embarked on a wave of M&A activity, beginning with the $38bn merger with Canadian mining and aluminium firm Alcan in 2007.