President Bush endorsed tax changes intended to help small investors recover from recent losses and feel better about the stock market. At his Waco, Texas, economic forum, Mr. Bush seized on two ideas floated by Charles Schwab, chairman of San Francisco investment-services firm Charles Schwab Corp.One idea would increase the amount of losses individual investors can take as tax deductions to $20,000 from $3,000. The other would reduce the so-called double taxation of stock dividends, to encourage chief executives to pay more in dividends and worry less about their companies' share prices and quarterly earnings.Although Mr. Schwab wasn't specific, the...