The Most Consequential Finance Decision After Valuation
The choice between debt and equity is the capital structure decision that shapes everything else: dilution, cost, risk, flexibility and the power dynamic between founders and their investors. It is also a decision that many early-stage founders and even some experienced finance leaders approach with insufficient rigour, defaulting to whichever instrument they understand best or whichever they have most recently seen others use.
The reality is that the optimal capital instrument changes materially at each stage of a company's development, and a structure that was appropriate at seed can become damaging at Series B. This article provides a systematic framework for making the debt versus equity decision at each growth stage, covers the specific debt instruments available to UK growth companies, and explains how to present a blended capital structure to existing and prospective investors.
When Debt Makes Sense at Each Stage
The central question in the debt versus equity decision is whether the company has sufficient visibility over future cash flows to service a debt obligation without threatening its operating plan. This visibility threshold changes as the company matures:
Pre-Revenue (Seed to Series A)
Equity is almost always the only viable option at pre-revenue stage. Lenders need cash flow to service interest and repay principal. A pre-revenue company has neither, and its only collateral is typically intellectual property that is difficult to value and harder still to realise. The exception is where founders have personal assets they are willing to pledge (unusual and inadvisable) or where a government-backed loan scheme provides guaranteed lending that does not require commercial cash flow underwriting.
The British Business Bank's Start Up Loans programme (up to £25,000 per founder) is an exception to this rule, providing government-backed unsecured loans at below-market rates for very early-stage businesses. However, this is personal lending, not company lending, and should be considered a founder capital contribution rather than a company debt instrument in the capital structure.
Post-Revenue with Predictable Cash Flow (Series A to B)
Once a company has recurring revenue with a predictable profile, debt becomes a genuine option. The key condition is predictability: a SaaS company with 95% gross retention and contracts averaging 18 months can service debt in a way that a marketplace company with lumpy, variable revenue cannot. For companies with predictable revenue, debt can be used to fund growth initiatives without issuing new equity, preserving the cap table for a future milestone round at a higher valuation.
Venture debt is the primary instrument at this stage. It typically provides three to twelve months of additional runway at a cost of base rate plus 7% to 9%, with warrants representing 10% to 20% of the loan value in equity upside for the lender. At a base rate of 4.75% (the approximate UK level entering 2025), the all-in cost of venture debt is approximately 12% to 14% per annum. This is expensive relative to post-2021 norms but is still non-dilutive if used well: the warrant dilution is a fraction of the dilution that would result from an additional equity round.
Asset-Rich Stage (Series B and Beyond)
Companies that have accumulated significant receivables, inventory, or other assets can access asset-based lending (ABL), which provides a credit line against the value of those assets. A fintech with a large loan book, a marketplace with significant working capital locked in receivables, or a SaaS company with predictable deferred revenue can all access ABL at rates substantially lower than venture debt. The advance rate (the percentage of the asset value that the lender will lend) varies by asset type: typically 80% to 85% of eligible receivables, 50% to 60% of inventory.
Debt Instruments Available to Growth Companies
The debt landscape available to UK growth companies is broader than many founders realise. Understanding the characteristics of each instrument is necessary to select the right one for the specific need.
Venture Debt
Venture debt is provided by specialist lenders (in the UK, providers include Silicon Valley Bank's UK operation, Kreos Capital, Claret Capital, and the British Business Bank's programmes) to VC-backed companies with demonstrated traction. Typically structured as a term loan of 12 to 36 months, with interest-only periods of three to six months at the start. The lender relies primarily on the company's ability to raise a future equity round to repay the loan, rather than on current cash flow alone. Warrants are standard.
Revenue-Based Financing
Revenue-based financing (RBF) is a form of debt where repayments are expressed as a percentage of monthly revenue rather than a fixed sum. This makes the repayment profile flexible: in strong months the company repays faster; in weak months it repays less. The total repayment is a fixed multiple of the advance (typically 1.2x to 1.5x), and there are no warrants. RBF is particularly well-suited to SaaS companies with predictable MRR. The effective annual interest rate, however, can be higher than it initially appears: a 1.35x repayment multiple over 12 months represents a cost of approximately 35%, which is significantly more expensive than venture debt but without the warrant dilution.
Asset-Based Lending
ABL provides a revolving credit line against specific assets on the balance sheet. Invoice discounting provides an advance against outstanding receivables (typically 80% to 85% of the face value of eligible invoices). Inventory finance provides credit against stock. For fintechs with loan books, warehouse facilities provide credit against the value of originated loans. ABL is usually the cheapest form of debt available to growth companies because it is secured lending: the lender has a direct claim on identifiable assets.
Term Loans and Revolving Credit Facilities
Traditional term loans and revolving credit facilities from commercial banks become available once a company has a track record of profitability or near-profitability and two to three years of audited accounts. These are priced at base rate plus a margin (typically 2% to 4% for a growth company), with covenants including minimum revenue levels, EBITDA-to-debt-service ratios, and sometimes equity raise conditions. The British Business Bank's Growth Guarantee Scheme provides government-backed lending for smaller amounts under this category.
Calculating the True Cost: WACC Framework
The weighted average cost of capital (WACC) provides a framework for comparing the total cost of a blended capital structure. The WACC is the weighted average of the cost of each capital component, where the weight is the proportion of that component in the total capital structure.
The cost of equity is the most difficult to calculate precisely. For a growth company, it can be estimated using the Capital Asset Pricing Model (CAPM) or, more practically, by reference to the IRR that equity investors expect to generate on their investment. For an early-stage UK growth company, this expected return is typically 25% to 40% per annum from the investor's perspective, which means the cost of equity from the company's perspective is high. Even at the lower end, equity is expensive capital if the company has the cash flow to consider alternatives.
The cost of debt is simpler: it is the interest rate paid, adjusted for the tax shield (interest on debt is deductible for corporation tax purposes, which reduces the effective cost). In the UK, with a corporation tax rate of 25%, a venture debt facility costing 13% gross has an after-tax cost of approximately 9.75%. Against a cost of equity of 30% or more, the case for incorporating debt into the capital structure when cash flow allows it is clear.
"The most common mistake is treating the equity round as the only option when revenues are strong enough to service debt. Every percentage point of additional dilution avoided through appropriate use of debt is a percentage point of value retained for founders and existing shareholders at exit."
The Decision Matrix
Presenting a Blended Capital Structure to Investors
When a company uses debt alongside equity in its capital structure, it must be presented thoughtfully to equity investors. Sophisticated investors understand WACC and the rationale for leverage; less experienced investors may conflate any debt with financial distress. The CFO's job is to frame the debt correctly as a deliberate capital structure decision, not as evidence of cash flow difficulty.
The key elements of the presentation are: the cost comparison (showing that the after-tax cost of the debt facility is materially lower than the cost of equity it replaced); the headroom analysis (demonstrating that the company can service the debt at conservative revenue assumptions, with at least 1.5x interest cover and visible repayment sources); and the strategic rationale (explaining why preserving equity for the next milestone round is the right allocation of capital).
Investors will also assess the debt covenants and the consequences of breach. If the debt facility includes covenants that could be triggered by a revenue shortfall, the investor needs to understand that the covenants are appropriately set relative to the business plan. Covenants set at 20% below the base case are protective; covenants set at 5% below the base case are a risk to the equity investors as well as the company.
Key Takeaways
- Equity is permanent, dilutive and has no fixed repayment; debt is temporary, non-dilutive but has a fixed cost and repayment obligation. The right choice depends on whether the company has the cash flow to service debt without threatening the operating plan.
- Pre-revenue companies are effectively limited to equity; post-revenue companies with predictable cash flow should actively consider whether debt is a lower-cost alternative for growth capital.
- Venture debt (base rate plus 7% to 9% plus warrants) is the primary debt instrument for VC-backed growth companies. At current UK rates, the all-in cost is approximately 12% to 14%; after-tax cost approximately 9% to 11%.
- Revenue-based financing is flexible but expensive: a 1.35x repayment multiple over 12 months implies a gross cost of approximately 35%. Suitable where predictability is high but warrant-based instruments are undesirable.
- Asset-based lending is the cheapest form of growth debt and becomes available once the company has significant receivables, inventory, or a loan book to pledge.
- The WACC framework is the correct tool for comparing debt and equity cost. At typical growth equity IRRs of 25% to 35%, the after-tax cost of debt is often 15 to 25 percentage points cheaper.
- Debt in the capital structure must be presented to equity investors with a clear headroom analysis and covenant explanation. Covenants should be set at a materially conservative level relative to the base case operating plan.
