ATLANTA—Porsche Cars North America has appointed Christian Koenig as vice president public relations, reporting to Detlev von Platen, president and CEO, and responsible for directing all public relations activities for Porsche in the United States. Before joining Porsche Cars North America, Koenig founded and led a consulting firm, specialized on market entry communications, media and government relations for international and domestic clients. Before that, he was senior vice president and head of corporate affairs for ThyssenKrupp North America.

CHICAGO—Derivatives clearing organization OCC has hired David Prosperi as first vice president, public relations, and Patricia Overstreet-Miller as first vice president, corporate communications, both reporting to newly appointed as executive vice president, business development Scot Warren. Prosperi served as vice president, global public relations, at Aon and has also held roles at CME Group and the Chicago Board of Trade. Overstreet-Miller was the top communications executive in North America for Zurich Insurance Co. and CCO for The McCormick Foundation.

VANCOUVER—Precious metals producer SilverCrest Mines has appointed Michael Rapsch as vice president, corporate communications. Rapsch spent the past three and a half years at SilverCrest, where he has been responsible for implementation, management and execution of all marketing and investor relations related programs.

MEMPHIS—Memphis International Raceway has hired Craig Wack as director of public relations and marketing. Wack previously worked as a motorsports writer for the Commercial Appeal in Memphis and was a public relations specialist for Geiger Media Global, serving clients in the motorsports world. Most recently, he worked at Academy Sports + Outdoors as an e-commerce content coordinator.