Buybacks also continue to be a popular use of corporate cash, as the same factors that create a promising environment for M&A ? low interest rates, light debt burdens, and CEO confidence ?also favor share repurchase programs. More than 50 percent of the companies in the Russell 1000 index are repurchasing their own shares, and Credit Suisse believes the trend has room to run. Firms are using only 34 percent of their aggregate free cash flow for buybacks, compared to 51 percent at the height of the last business cycle in 2007.