German businesses’ expectations about the six months ahead have seen the biggest improvement for at least 18 years, as a generally brighter mood points to robust third-quarter growth in Europe’s biggest economy.

The Munich-based Ifo institute said on Wednesday that its business climate index had risen for a fifth consecutive month, from 87.4 in July to 90.5 in August. That was the highest since September 2008, before the intensification of the global economic crisis following the collapse of Lehman Brothers.