I don't know how much of that $3 million is profit, but you could possibly sell that off at a price-point of around $2,5 million, allowing the investor to make

I don't know how much of that $3 million is profit, but you could possibly sell that off at a price-point of around $2,5 million, allowing the investor to make $500,000 simply by carrying the risk. Bankers sell debt off all the time and in your case, you will simply be selling off future earnings at a discounted rate. You have to be really savvy about how you structure it though and not take it on as a loan of any sort. You mentioned to someone else how notoriously difficult it is to get payments from the building industry, which is probably a red flag that the bankers are indirectly hinting at you (and something you need to always structure your business around).