Related party transactions

Our significant related party transactions occurring during the nine months ended September 30, 2017 and 2016 are described below. We believe that all of the transactions with our related parties were on terms that approximate market.

Glencore ownership

As of September 30, 2017, Glencore plc and its affiliates (together "Glencore") beneficially owned 42.9% of Century’s outstanding common stock (47.4% on a fully-diluted basis assuming the conversion of all of the Series A Convertible Preferred Stock) and all of our outstanding Series A Convertible Preferred Stock. From time to time Century and Glencore enter into various transactions for the purchase and sale of primary aluminum, purchase and sale of alumina, tolling agreements and certain forward financial contracts.

Sales to Glencore

For the three months ended September 30, 2017 and 2016 we derived approximately 75% and 90%, respectively, of our consolidated sales from Glencore, while for the nine months ended September 30, 2017 and 2016, approximately 76% and 89%, respectively, of our consolidated sales were derived from Glencore.

We have entered into agreements with Glencore pursuant to which Glencore has agreed to purchase aluminum produced from our U.S. and Icelandic operations through 2017. Glencore purchases aluminum produced at our North American smelters at prices based on the London Metal Exchange (the "LME") price for primary aluminum plus the Midwest regional delivery premium and any additional negotiated product premiums. Glencore purchases aluminum produced at our Grundartangi, Iceland smelter in 2017 at prices based on the LME plus the European Duty Paid premium and any applicable product premiums.

Glencore purchases the aluminum we produce for resale.

Purchases from Glencore

We purchase alumina from Glencore under a long-term supply agreement and on a spot basis. Pursuant to our current agreement, Glencore has agreed to supply us with alumina through 2017 at prices indexed to the LME price of primary aluminum. In 2016 and 2017, upon mutual agreement, all of our purchases from Glencore under this agreement were priced based on a published alumina index.

Financial contracts with Glencore

During 2017, we entered into certain financial contracts with Glencore. Refer to Note 13 Derivatives to the consolidated financial statements included herein.

Transactions with Baise Haohai Carbon Co., Ltd. ("BHH")

We own a 40% stake in BHH, a joint venture that owns a carbon anode and cathode facility located in the Guangxi Zhuang Autonomous Region of south China. We have an agreement with BHH to provide carbon anodes to Grundartangi through December 31, 2017.

Summary

A summary of the aforementioned significant related party transactions for the three and nine months ended September 30, 2017 and 2016 is as follows:



	Three months ended September 30,				Nine months ended September 30,
	2017		2016		2017		2016
Net sales to Glencore	$	299,235	$	301,111	$	876,079	$	871,771
Purchases from Glencore	81,905		62,317		195,073		156,507
Purchases from BHH	3,248		2,568		9,137		7,666