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Andy Riethmaier, July 14 2025

Understanding the True Cost of Capital: What Every Founder Needs to Know

Raising capital is often seen as a major milestone and rightly so. But too often, founders and business owners celebrate a successful raise without fully understanding the long-term cost of that capital.

The true cost of capital goes far beyond interest rates or equity dilution. Whether you're funding growth, an acquisition, or a runaway extension, knowing how much that money really costs can make or break your company's financial future. 


1. Cost of debt: It's Not Just the Interest Rate

At first glance, debt seems straightforward-borrow money, pay interest, pay it back. But there's more to it.

Cheap debt can be powerful but restrictive terms can quietly drain your flexibility.


2. Cost of equity: The most expensive money you'll ever raise

Equity doesn't come with a monthly payment but it can cost you far more:

Equity is great for high-risk, high-reward growth- but it's not "free money"


3. WACC: The Weighted Average Cost of Capital

For growing companies, the Weighted Average Cost of Capital (WACC) is a useful metric that blends debt and equity into a single number. It helps answer: " How much does it cost on average to fund every dollar we invest into our business?"

Keeping WACC low means more of your profits go to you-not your financiers.


4. Opportunity Cost: What Are You Giving Up?

Capital might unlock growth-but it also sets a bar for what your returns need to beat. If your cost of capital is 12%, your projects need to return more than that just to break even.

Every raise should be judged not only by how much it gets you today-but by the return you'll need tomorrow.


Final Thoughts

The best founders don't just raise capital- they raise it intelligently. By understanding the full cost-financial, strategic, and operational-you'll make decisions that create lasting value, not just short-term funding

Written by

Andy Riethmaier

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