The Munich-based Ifo institute’s index of western German business sentiment rose for the fifth consecutive month in September from 90.8 in the previous month to 91.9, raising hopes of a moderate turnaround for Europe’s largest economy. Germany has been bogged down in near-zero growth for three straight years and the economy shrank 0.1 percent in the second quarter. However, Ifo institute head Hans-Werner Sinn warned against premature euphoria. "The worsening of conditions that is visible in all sectors against the previous month urges caution," he said. Sinn said the gain in the index, based on a survey of 7,000 companies, was led by increased optimism among manufacturers and retailers, while construction companies turned more pessimistic during the month. "These are the first positive signs, but it’s not a self-sustained recovery yet," Heinrich von Pierer, chief executive officer of Siemens AG, Germany’s largest engineering company, told DPA. "An imported recovery is likely."