Anadarko Petroleum Corp. has expanded its share repurchase program to $4 billion, a $1 billion increase, after completing the first $3 billion in repurchases at the end of June. The board also announced a $500 million increase to its debt-reduction program, bringing the total planned to $1.5 billion. The stock buyback and debt reductions, authorized to the end of June 2019, raise the aggregate equity and debt-buyback programs to $5.5 billion, in addition to the recent increase of about $400 million annualized to the common dividend. Share repurchases are to be made from time to time in open market or private transactions, depending on market conditions, and may be discontinued at any time.