The verdict in three sentences
A SaaS data room billed at EUR 3,000 to 15,000 per deal (or EUR 0.40 to 0.85 per page) remains the right choice below 6 to 8 deals a year. Above that, a custom data room at EUR 60,000 to 120,000 excl. VAT, hosted for EUR 300 to 900 a month, reaches break-even after 10 to 14 cumulative deals. For a London M&A boutique running 8 to 15 deals a year, 3-year savings often exceed EUR 80,000, plus a platform branded with the firm's name.
What an M&A data room must do
Buyers, their advisers and their banks spend weeks in the data room. The expected features are well known, and each has an identifiable build cost.
| Feature | Role in the deal | Estimated effort | Indicative 2026 cost (EUR) |
|---|---|---|---|
| Folder structure and automatic indexing | Document numbering, exportable index | 8 to 12 days | 5,000 to 8,500 |
| Permissions by lot and by bidder | Each bidder sees only its scope | 12 to 18 days | 8,000 to 13,000 |
| Dynamic watermark and secure viewer | Name, date and IP on every page, downloads blocked | 15 to 20 days | 10,000 to 15,000 |
| Q&A module | Questions per bidder, routing to experts, deadlines | 12 to 18 days | 8,000 to 13,000 |
| Audit log and activity reports | Who read what and for how long, interest signals | 10 to 15 days | 6,500 to 11,000 |
| Bulk upload, OCR and full-text search | 5,000 to 30,000 pages per deal | 10 to 15 days | 6,500 to 11,000 |
| Security (MFA, encryption, penetration test) | Required by institutional buyers | 15 to 30 days | 15,000 to 48,500 |
The total ranges from EUR 60,000 to 120,000 depending on finish, delivered in 3 to 5 months.
Total 3-year cost by deal volume
The table compares a SaaS data room at an average of EUR 6,500 per deal (2026 order of magnitude for 5,000 to 15,000 pages) with a EUR 90,000 custom platform, hosted at EUR 600 a month and maintained for EUR 12,000 a year from year two.
| Deal volume | SaaS over 3 years | Custom over 3 years | Difference |
|---|---|---|---|
| 4 per year (12 total) | EUR 78,000 | EUR 135,600 | SaaS cheaper by EUR 57,600 |
| 6 per year (18 total) | EUR 117,000 | EUR 135,600 | SaaS cheaper by EUR 18,600 |
| 8 per year (24 total) | EUR 156,000 | EUR 135,600 | Custom cheaper by EUR 20,400 |
| 12 per year (36 total) | EUR 234,000 | EUR 135,600 | Custom cheaper by EUR 98,400 |
| 15 per year (45 total) | EUR 292,500 | EUR 137,500 | Custom cheaper by EUR 155,000 |
The custom cost barely moves with volume: only storage grows, by a few dozen euros a month. That is why the decision becomes so clear above 8 deals a year.
Risks to weigh before deciding
The first risk is buyer confidence: a US private equity fund knows the big data room brands and may ask for assurances. ISO 27001 certified hosting, an annual penetration test (EUR 6,000 to 10,000) and an exportable audit log answer most objections. The second risk is availability: a data room down the day before a bid deadline is costly, hence a maintenance contract with a 4 business hour response time. On UK GDPR and confidentiality, hosting in the UK or EU with a certified provider simplifies compliance questionnaires.
Mini case study
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Julien, partner at an M&A boutique in London, runs 10 deals a year and pays an average of EUR 7,200 per data room, i.e. EUR 72,000 a year. He commissions a platform for EUR 85,000, hosted for EUR 500 a month, with EUR 10,000 a year of maintenance from year two. After 14 deals (about 17 months), SaaS would have cost him EUR 100,800 against EUR 97,700 for his platform: break-even is reached. Over 3 years, spend drops from EUR 216,000 to EUR 123,000, a EUR 93,000 saving, and every new mandate is pitched with a data room in the firm's colours.
FAQ
From how many deals is a custom data room profitable?
Break-even usually falls between 10 and 14 cumulative deals. Below 6 deals a year, SaaS stays cheaper over 3 years.
How long does it take to build?
Allow 3 to 5 months, including 3 weeks of scoping. A core version (permissions, watermark, audit log) can be live in 10 weeks for an urgent mandate.
Will foreign buyers accept a firm-built data room?
Yes, if the safeguards are documented: ISO 27001 hosting, MFA, a penetration test less than 12 months old. These cost EUR 8,000 to 15,000 a year.
Can the data room be recharged to the sell-side client?
It is common practice: many firms recharge EUR 3,000 to 6,000 per deal, which speeds up payback.
What happens to the data after closing?
The platform archives the data room read-only and produces a certified copy (encrypted drive or export) for the parties. Deletion follows the period set in the engagement letter, often 5 to 10 years.
Let's scope your project. Tell us your deal volume and security requirements: we will price a custom data room, its hosting and its real break-even against your current SaaS. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
