1) CM's generally charge 2-5% of the contract value if they are not at risk. Very few GC's would consitently bid 3% and stay around long. CFMA lists overall profits and it is generally aound 5% This figure is net(after tax which for business is around 50%) for all contractors in heavy highway. This is an estimated amount of what the industry as a whole did, which includes good jobs and bad jobs. There are many jobs done at a loss every year, and every contractor has had his share of bad jobs. Therefore the margins are kept up a little.
2) Contracting is a very high risk capital intensive business. Business cyles flucutate much more than many other industries. Nobody is in this for 3%
3) Perhaps in residential work contractors can get up front payments, but in most heavy highway contracts, invoices are monthly and payment is 30 to 60 days later. Contractors do try to get as much money as early as possible, but it generally is not a significant percentage of the contract, is used for costs that wont be paid until later in the contract and supports administrative costs of starting the work.
4) There is not sufficent cash flow in a project to do a $100 million project on 10 million cash.Further Contractors, banks and surities do not look at profit on cash flow. Profit for a job is project revenues less direct project costs divided by direct project costs. Cash flow is never considered.
5) If a contractor makes 10% overhead and 10% profit on a project, and the first 10% truely represents his overhead cost on the project, Then any minority share holder dividends would be paid and taxes would be paid (neiher would come out of OH) thus the net profit would be 5-4% net.
Thus I think the 10% + 10% sounds reasonable.