The document discusses whether companies' cash flows can continue to support high levels of share repurchases. It notes that share buybacks by S&P 500 companies have increased significantly in recent years and are expected to rise further in 2015. However, the document argues that cash flows at some companies may come under pressure due to rising costs from restructuring programs and pension obligations. It examines four companies - Cisco, General Mills, Coca-Cola, and Philip Morris - that have high buyback levels but may face tightening cash flows due to factors like declining margins, negative sales growth, and increasing debt. The document questions whether such companies can sustain high repurchases and whether buybacks represent the best use of corporate cash.