Cost of debt is the effective interest rate a company pays on its borrowed funds. It includes interest payments, loan fees, and other financing costs expressed as a percentage. When evaluating investments, savvy investors use cost of debt to understand how efficiently a company uses leverage and whether debt levels are sustainable relative to cash flow and earnings.
How It Works
Cost of debt is calculated by taking total interest expenses and dividing by total debt outstanding, or by examining the weighted average interest rate across all borrowing sources. A startup with a $500,000 bank loan at 8% annual interest has a cost of debt of 8%. However, the true cost is often lower because interest payments are tax-deductible—reducing the after-tax cost. The formula adjusts: After-Tax Cost of Debt = Interest Rate × (1 - Tax Rate). This tax benefit makes debt cheaper than it appears on the surface.
Why It Matters for Investors
Cost of debt reveals critical information about a company's financial health and risk profile. A high cost of debt signals that lenders view the company as risky, charging premium rates. Conversely, low-cost debt indicates strong creditworthiness. For angel investors, this metric helps assess whether a startup's debt burden is manageable and whether the company is using leverage strategically or dangerously. It also factors into the weighted average cost of capital (WACC), which determines the minimum return investments must generate to create shareholder value.
When comparing investment opportunities, higher cost of debt often means higher financial risk and pressure on margins. A pre-revenue startup with expensive debt from personal loans might struggle to scale, while a profitable SaaS company securing institutional credit at favorable rates demonstrates strength.
Example
Imagine two B2B software companies seeking investment. Company A secured a $2 million venture debt facility at 12% annually. Company B negotiated a $2 million bank line of credit at 6%. Company A's higher cost of debt reflects greater perceived risk—perhaps volatile revenue or shorter runway. As an investor, you'd investigate why lenders demand 12% versus 6%. This gap signals something important about cash flow predictability, market traction, or management experience that affects your investment decision.
Key Takeaways
- Cost of debt is the interest rate and fees a company pays on borrowed capital, expressed as a percentage
- The after-tax cost of debt is lower than the stated rate because interest expenses reduce taxable income
- Rising cost of debt signals increasing financial risk and lender concern about repayment ability
- Compare cost of debt against expected returns and cost of equity to evaluate a company's capital structure and investment viability