Debt financing occurs when a firm sells fixed income products, such as bonds, bills, or notes to investors to obtain the capital needed to grow and expand its operations. When a company issues a bond, the investors that purchase the bond are lenders who are either retail or institutional investors that provide the company with debt financing. The amount of the investment loan referred to as the principal must be paid back at some agreed date in the future. If the company goes bankrupt, lenders have a higher claim on any liquidated assets than shareholders.
When a company issues debt, not only does it promise to repay the principal amount, it also promises to compensate its bondholders by making interest payments, known as coupon payments, to them annually. The interest rate paid on these debt instruments represents the cost of borrowing to the issuer. Source: Investopedia
However, there will always be a risk where companies will be unable to pay investors for the first few years and so investors will not be able to make their 15% or more return.