Wolfgang Franz, head of Germany's ZEW Center for European Economic Research said Tuesday that investor confidence in Europe's largest economy rose unexpectedly for the second month in July amid optimism that a spurt in exports will help bolster consumer spending and corporate investment. Exports, which account for about one-third of the German economy, soared for the fifth month in May. The ZEW said its investor confidence index rose to 48.4 from 47.4 in June. The ZEW surveys around 300 economic analysts and institutions every month for their medium-term expectations for economic growth and development of capital markets. The index reflects the difference between the positive and negative estimates for economic development in Germany for the next six months.