Trust, in an economic sense, is how much material is being dedicated towards a corporation's future existence... A corporation can be an individual, or a company of individuals...
By "how much material is being dedicated toward...[it's]...future existence" you presumably mean how much the firm or individual is investing in relation to their income or some similar measure. That can be part of it, but definitely isn't all of it. All market transactions are, contrary to the technocratic worldview of mainstream political economists, human transactions. The actual underlying human relationships matter, and the balance sheets only matter inasmuch as they facilitate communications between actual people.