Stocks edged up, and all major indexes rose, but the gains were led by the riskier parts of the market. The Russell 2000 index of small-company stocks climbed a fourth straight day. The Dow transportation average, a leading indicator for the broader economy, also jumped. The gains suggest investors are getting more confident about the economy. In the first half of the year, stock markets were powered by safer companies that paid big dividends. Wall Street is also turning its attention to earnings. They should give investors fresh insight into the economy. Stocks have hit a series of highs this year on expectations earnings will remain at record levels.