Organic growth is the increase in a company's revenues and earnings generated by its own activities — commercial development of the existing customer base, new client acquisition, new product or service launches, or geographic expansion — without recourse to external acquisitions. It contrasts with external growth (build-up, M&A) which increases company size through integration of third-party entities.

Organic growth is the primary quality criterion analysed by investors and business valuators: high and recurring organic growth signals intrinsic competitiveness, durable pricing power and structural demand for the company's offering. In DCF valuation models, the projected organic growth rate is one of the most determinative business plan assumptions — a 2 percentage point growth difference (4% vs 6%) over 5 years represents a 10–15% cumulative revenue gap and an 8–12% valuation difference.

Organic growth rate is calculated by adjusting total revenue for the impact of acquisitions: organic growth = (Year N revenue - Year N-1 pro forma revenue excluding acquisitions) / Year N-1 pro forma revenue. This calculation requires detailed analysis of client contracts and cohorts.

Example: a Swiss engineering consultancy shows +18% revenue growth between N-1 (CHF 6.0M) and N (CHF 7.1M). Of which: +CHF 0.6M linked to a N-1 acquisition (pro forma), +CHF 0.5M from organic new clients. Actual organic growth: CHF 0.5M / CHF 6.0M = +8.3% — a solid rate, validated during due diligence as representative of healthy commercial momentum.

At Hectelion, we systematically distinguish organic and external growth in our financial analyses, to assess the intrinsic quality of our clients' commercial performance.