IGO stands for the Inpector General's Office. The inspector general is an official in the government who investigates the operations of government and issues reports and his/her findings.
How It's Used
"The IGO's report points out that public-private partnerships are common in Europe and Australia; presumably some of them work out OK. Some scoff at the notion that the city would ever have raised parking rates on its own, however much money it might have made in theory. But the deal could have been structured differently. The IGO suggests a 50-50 revenue split over a 20-year term would have generated enough cash to cover the city's budget needs while giving the city more control. (The report also says the deal could have been adjusted so parking rates went up less, but it's pretty clear they were going to go up.)"