He argues that investors are not only sending a message to Glencore chief executive Ivan Glasenberg about the need for a less leveraged balance sheet, they are also sending a message to BHP Billiton and Rio Tinto about their unsustainable dividend policies.
In the context of the input sentence, determine the relationship between 'Glencore' and 'Ivan Glasenberg'.
Options: member of, stock exchange, publisher, owned by