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.
What is the relationship between 'Glencore' and 'Ivan Glasenberg' in the context of the input sentence.
Options: publisher, stock exchange, member of, owned by