its ownership stake had risen to 9.8% by 2014, making it Rio Tinto's biggest investor. The proposed investment structure reportedly involves $12.3 billion for the purchase of ownership interests of Rio Tinto assets in its iron ore, copper and aluminium operations, plus $7.2 billion for convertible bonds. The transaction would bring Chinalco's ownership of the company to roughly 18.5%. The deal is still pending approval from regulators in the United States and China, and has not yet been approved by shareholders, although regulatory approval has been received from Germany and the Australian Competition & Consumer Commission. The largest barrier to completing the investment may come from Rio Tinto's shareholders; support for the deal by shareholders was never overwhelming and has reportedly declined in 2009, as other financing options (such as a more traditional bond issuance) are beginning to appear more realistic as a viable alternative funding source. A shareholder vote on the proposed deal was expected in the third quarter of 2009. Rio Tinto is believed to have pursued this combined asset and convertible bond sale to raise cash to satisfy its debt obligations, which required payments of $9.0 billion in October 2009 and $10.5 billion by the end of 2010. The company has also noted China's increasing appetite for commodities, and the potential for increased opportunities to exploit these market trends, as a key factor in recommending the transaction to its shareholders. In March 2010, it was announced that Chinalco would invest $1.3 billion for a 44.65% stake in Rio Tinto's iron ore project in Simandou, Guinea. Rio Tinto retained 50.35% ownership at Simandou. In November 2011, Rio joined with Chinalco to explore for copper resources in China's complex landscape, by setting up a new company, CRTX, 51% owned by Chinalco and 49% by Rio Tinto. Management Under the company's dual-listed company structure, management powers of the Rio Tinto are consolidated in a single senior management group led by a board of directors and executive committee. The board of directors has both executive and non-executive members, while the executive committee is composed of the heads of major operational groups. Board of Directors Executive Directors Dominic Barton, chairman Jakob Stausholm, chief executive Non-Executive Directors Megan Clark AC Hinda Gharbi Simon McKeon AO Simon Henry Jennifer Nason Sam Laidlaw Ngaire Woods CBE Rio Tinto engages professional lobbyists to represent its interests in various jurisdictions. In South Australia, the company in represented