Explicit demand signal? The only way you can do that today is through gift cards. In principle the company could issue gift cards at a discount and if they were

Explicit demand signal? The only way you can do that today is through gift cards. In principle the company could issue gift cards at a discount and if they were tradeable, then "investors" into the gift cards would hold onto them until the gift cards are worth more than they originally paid for. There are also Genussrechte in Germany which are commonly used to pay interest not as money but as gift cards which can only be used at the company you invested in. This is done to fund local bakeries where the future customers essentially pay upfront for their consumption in exchange for receiving a return.