Since the company's stock recovered, Mr. Glasenberg has engineered the purchase of a stake in Russian state oil company PAO Rosneft, taken full control of a Congolese mine and made an offer to take over agricultural trader Bunge Ltd. Mr. Glasenberg has long coveted Rio Tinto's coal assets because they sit near some of Glencore's Australian coal operations, offering opportunities for cost savings were they to merge. "The probability of Glencore gaining these assets has increased in our view," RBC Capital Markets said in a note on Friday. A Glencore takeover of Rio's coal assets would hand more control to a company that is already one of the biggest coal traders in the world. Rio has touted Yancoal's approval from regulators in China, a voracious consumer of coal.