Now I have a couple of quotations from different contractors and most require 30% downpayment to as high as 50%. Reason being they need to buy the materials to protect from price increase. For a 4M project, that is 1.2M to 2M outright payment. What kind of guarantee/documents would you ask them to ensure that they will not disappear with the money.

Are there insurance products to cover from such losses? Is having a PCAB license a guarantee of?