The company logo of Noble Group is displayed at its office in Hong Kong, China. REUTERS

Embattled commodities trader Noble Group on Tuesday said it completed the sale of U.S.-based coal unit, MR Coal Marketing for US$34.5 million to an unnamed buyer.

The sale, made by a Noble's unit Noble Americas Emerald Corp, was undertaken after the buyer had exercised a call option, which was granted by Noble in 2015 in connection with Noble's initial acquisition of MR Coal in the same year.

"The grant of the call option which is not exercisable at the discretion of the group did not amount to a disclosable transaction for the purposes of Chapter 10 of the listing manual of the Singapore Exchange Securities Trading Limited at the time of grant of the option," Noble said.

The book value and net tangible asset value of MR Coal was around US$35.6 million as of September 30.

Following the completion of the MR Coal disposal, the company has ceased to be a subsidiary of Noble Group.

Shares in Noble rose 7 percent to S$0.15 on the Singapore Exchange.