The leading economic index rose 1.2% in August, the Conference Board said Friday. This is a slower pace than the revised 2% rise in July and 3.1% gain in June. “The slowing of the improvement suggests that this summer’s economic rebound may be losing steam heading into the final stretch of 2020,” said Ataman Ozyildirim, director of business cycles research at the board. The LEI is a weighted gauge of 10 indicators designed to signal business-cycle peaks and valleys.