Related party transactions

The significant related party transactions occurring during the nine months ended September 30, 2018 and 2017 are described below. We believe all of our transactions with Glencore and BHH are at prices that approximate market.

Glencore ownership

As of September 30, 2018, 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. See Note 6. Shareholders' equity for a description 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, and certain forward financial contracts.

Sales to Glencore

For the three months ended September 30, 2018 and 2017 we derived approximately 63% and 75%, respectively, of our consolidated sales from Glencore, while for the nine months ended September 30, 2018 and 2017 we derived approximately 63% and 76%, respectively, of our consolidated sales from Glencore. Glencore purchases the aluminum we produce for resale.

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 2018 and 2019, respectively. Glencore purchases aluminum produced at our North American smelters at prices based on the London Metal Exchange (the "LME") plus the Midwest regional delivery premium and any product premiums. Glencore purchases aluminum produced at our Grundartangi, Iceland smelter at prices based on the LME plus the European Duty Paid premium and any product premiums.

Purchases from Glencore

We purchase a portion of our alumina requirements from Glencore. Alumina purchases from Glencore during the nine months ended September 30, 2018 were priced based on a published alumina index.

Financial contracts with Glencore

We have certain financial contracts with Glencore. See Note 13. Derivatives regarding these forward financial sales contracts.

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

We own a 40% stake in BHH and purchase carbon anodes from them for use in our aluminum production operations.

Summary

A summary of the aforementioned significant related party transactions is as follows:



	Three months ended September 30,				Nine months ended September 30,
	2018		2017		2018		2017
Net sales to Glencore	$	305.3	$	299.2	$	884.2	$	876.1
Purchases from Glencore	57.2		81.9		205.6		195.1
Purchases from BHH	5.9		3.2		21.4		9.1