Final answer:
Common shareholders bear the greatest risk in financial investments as they're last in line during asset liquidation and hence should earn the highest returns.
Step-by-step explanation:
The suppliers of funds who bear the greatest risk and should therefore earn the greatest return are the common shareholders. Common shareholders are the last to be paid in the event of a company's liquidation and have potential for unlimited gains, mirroring their risk level. On the other hand, bondholders, general creditors like banks, and preferred shareholders have more security since they have a higher claim on assets and fixed income returns.
Issuing bonds or borrowing from banks involves making regular interest payments regardless of the firm's income, allowing the firm to retain control over its operations. Meanwhile, issuing stock means selling ownership in the company, and comes with no obligation to make payments, but it dilutes control and makes the firm answerable to shareholders.