Scalability

What is scalability?

Scalability (German: Skalierbarkeit) refers to the ability of a business model to increase revenue and output considerably while costs, staff and organisation grow only less than proportionately. A scalable company improves its margin as revenue grows, because each additional euro of revenue causes lower additional costs than the existing revenue does on average. The difference becomes clear with a piece of music: a concert reaches only the audience in the hall, whereas a recording can be sold any number of times without significant additional cost. In German, Skalierungsfähigkeit is a common synonym, and in the technical sense also Erweiterbarkeit (extensibility).

The term has two meanings that are often mixed up. Economic scalability concerns the course of costs and margin as revenue grows; technical scalability concerns the ability of software and infrastructure to process a growing load. Investors and buyers generally mean the economic meaning. It determines whether additional capital produces earnings disproportionately, and it therefore lies at the centre of the equity story, financial model and valuation. It is examined in financial, commercial and technical due diligence.

Economic scalability: marginal costs and gross margin

The starting point is the question of what the next customer or the next unit of output costs in addition. These marginal costs, essentially variable costs, consist of the cost of revenue, such as cloud costs, third-party licences, payment processing, customer onboarding and customer service, and of the costs of customer acquisition. The lower they are in relation to the price, the more of the additional revenue covers the fixed costs that arise for development, administration and management independently of the number of customers.

The most important measure is the gross margin, that is, revenue less cost of revenue in relation to revenue. Besides its level, its trend counts above all: if the gross margin rises as revenue grows because onboarding and operation become standardised, this speaks for a scalable model. If it remains constant or falls, a significant cost block grows along with revenue. If fixed costs also grow more slowly than revenue, operating profit rises faster than revenue (operating leverage). The incremental margin shows how much of each additional euro arrives in earnings.

Formula: incremental margin = change in earnings ÷ change in revenue

Gross margin in German annual financial statements

The gross margin cannot always be taken directly from a German annual financial statement. Only the income statement under the cost of sales method shows a gross profit on revenue (Section 275(3) of the German Commercial Code, Handelsgesetzbuch, HGB). Under the more widespread total cost method (Section 275(2) HGB), the costs of customer service and onboarding sit in personnel expenses, and cloud costs in cost of materials or in other operating expenses. The gross profit (Rohertrag) of the management accounts (betriebswirtschaftliche Auswertung) also usually deducts only cost of materials and goods. For investors, the gross margin is therefore derived through an allocation of accounts or cost centres, which the financial due diligence reviews.

Organisational scalability

Many business models run up against organisational limits earlier than technical ones:

• Staff-dependent services: If every additional customer requires additional hours for onboarding, customisation or support, staff grows in proportion to revenue, and recruiting limits growth.
• Dependence on founders: If sales closings, key customer relationships or technical decisions run through one or two people, their time limits growth. In a company sale, this counts as a key person risk.
• Manual processes: Contract set-up, invoicing and dunning, which work by hand with a few customers, become a cost block and a source of errors as the number of customers grows.
• Management structure: Beyond a certain size, a company needs a second management level, documented processes and controlling. The headcount plan shows whether this build-up is reflected in the financial model.

Technical scalability: vertical and horizontal

A system is technically scalable if it processes growing numbers of users, volumes of data and transactions with stable performance. Vertical scaling uses more powerful machines for this, and horizontal scaling distributes the load across additional servers working in parallel. This is a necessary but not a sufficient condition of economic scalability.

Infrastructure costs per user or transaction are economically relevant. If an application purchases computing power from external AI models for every request, the cost of revenue grows with usage, and the gross margin depends on the pricing model and purchasing terms. In technical due diligence, the architecture, load limits and accumulated technical debt are examined, that is, deferred rework on the software. If an architecture has to be rebuilt at significantly higher load, an investment requirement arises that is often missing from the plan.

How investors examine scalability

In a financing round and a company purchase, scalability is evidenced by time series. Usual test measures are:

• Gross margin over time across several quarters, separated into recurring revenue and services revenue.
• Incremental margin between periods and the share of fixed costs in revenue over time.
• Revenue per full-time employee and the ratio of staff in onboarding and customer service to the number of customers.
• Sales efficiency, measured for example by the CAC payback period, the number of months until the acquisition costs of a customer have been recovered, and by the ratio of customer value to acquisition costs.

Valuations based on revenue multiples (revenue multiple), in which the enterprise value is set as a multiple of revenue, assume that future revenue produces earnings disproportionately. Investors apply discounts to a planned margin expansion without a proven cost trend.

Worked example: scalability of two software companies

Two software companies each generate revenue of EUR 4.0 million with break-even earnings. A onboards each customer in projects lasting several weeks, while B relies on standardised set-up by the customer. At A, therefore, three quarters of the cost of revenue is attributable to staff in onboarding and operations, at B one quarter; one full-time employee costs EUR 80,000 a year. Both plan to double revenue to EUR 8.0 million; in the plan, cost of revenue and sales costs grow in proportion to revenue, and the costs of development and administration by 20%.

• A today: cost of revenue EUR 1.6 million (gross margin 60%), sales EUR 1.2 million, development and administration EUR 1.2 million, earnings 0
• B today: cost of revenue EUR 0.8 million (gross margin 80%), sales EUR 1.2 million, development and administration EUR 2.0 million, earnings 0
• A after doubling: cost of revenue 3.2 plus sales 2.4 plus development and administration 1.44 gives EUR 7.04 million of costs; earnings 8.0 minus 7.04 = EUR 0.96 million; margin 12.0%
• B after doubling: cost of revenue 1.6 plus sales 2.4 plus development and administration 2.4 gives EUR 6.4 million of costs; earnings 8.0 minus 6.4 = EUR 1.6 million; margin 20.0%
• Incremental margin A: 0.96 ÷ 4.0 = 24.0% per additional euro of revenue
• Incremental margin B: 1.6 ÷ 4.0 = 40.0%
• Additional cost of revenue: A 3.2 minus 1.6 = EUR 1.6 million; B 1.6 minus 0.8 = EUR 0.8 million
• Additional positions A: EUR 1.6 million × 0.75 = EUR 1.2 million ÷ 80,000 = 15 positions
• Additional positions B: EUR 0.8 million × 0.25 = EUR 0.2 million ÷ 80,000 = 2.5 positions

From the same starting point, B achieves earnings that are EUR 0.64 million higher after the doubling and needs only one sixth of A's additional positions in onboarding and operations. The difference arises mainly in the cost of revenue: of each additional euro of revenue, B retains 80 cents after cost of revenue, A only 60 cents. Investors therefore consider a higher revenue multiple justified for B, although both companies report the same revenue and the same earnings today.

Distinctions: scalability, growth, economies of scale, network effects

• Growth: describes the increase in revenue. A company can grow strongly without being scalable if costs rise to the same extent; the growth is then bought with capital and staff.
• Economies of scale: falling unit costs through larger volumes, for example because fixed costs are spread over more units (fixed cost degression) or purchasing becomes cheaper. Economies of scale are one cause of scalability but do not capture bottlenecks in staff and organisation.
• Network effects: increase the value of a product with each additional user and act on the demand side, whereas scalability describes the cost side. Both can reinforce each other.

Common mistakes

• Claiming scalability instead of evidencing it. The statement that the model scales is no substitute for a time series of gross margin and cost per customer. Investors recalculate the cost trend from the monthly financial statements.
• Equating software with scalability. Software can grow technically without limit and still not scale economically if onboarding, customisation and support per customer remain staff-intensive.
• Implementing every special request. Customer-specific development increases revenue in the short term and maintenance costs permanently, until the product has become a project business.
• Scaling too early. If sales capacity is built before product and unit economics are sound, growth multiplies the losses instead of reducing them.

Frequently asked questions

Can a service company be scalable?

Yes, within limits. Standardised service packages at fixed prices, reusable building blocks and the shifting of routine work into software raise the margin as revenue grows. The extent generally remains below that of standard software because part of the service stays tied to people.

When is the right time to expand sales and organisation?

When product-market fit has been demonstrated and each new customer brings in more over its lifetime than its acquisition and support cost.

How is scalability reflected in the financial model?

Through separate cost drivers. Cost of revenue and staff in onboarding and service are derived from the number of customers and productivity per position, fixed costs from the planned organisational build-up. A model that plans all costs as a fixed percentage of revenue can neither show nor refute scalability.

How does scalability affect the purchase price?

Directly via the valuation multiple: models with a high and rising gross margin generally receive higher multiples than models with a high share of services. Strategic buyers additionally examine whether the product can be distributed through their own sales organisation without a proportional build-up of staff.

The Roemer Capital view

In preparing financing rounds, we distinguish between capital-ready companies, which can service loans, and investor-ready companies, which are structurally able to grow disproportionately with external capital. Scalability makes the difference: only if additional revenue produces earnings disproportionately does equity capital pay off for investors.

In the financial model, we therefore evidence scalability with figures rather than with a classification of the business model. The course of gross margin, staff per customer and incremental margin is shown across the history and at least three plan years. If staff in onboarding and service grows in proportion to revenue in the plan, the plan may be realistic, but it does not support a valuation with high revenue multiples. Then either the process or the valuation expectation has to change.