Do not buy technology due diligence unless a result will alter the cost or the initial hundred days of ownership. If neither moves, you are commissioning a document, and a document is the most expensive thing a deal team can read.
That test looks severe until it meets a calendar. DFIN's guide to technical due diligence says that the average merger or acquisition takes five to six months in total, and the technology track occupies a fraction of it. Work that does not fit the window gets compressed, skipped, or delivered after the investment committee has formed its view.
The consequence shows up in the numbers. MEV's technical due diligence guide cites KPMG's finding that 62% of deals fall below their financial targets, mostly because diligence was weak. The technology track is often where that weakness is located, as it is the track that yields the number no one has put in the model yet.
Three versions of the same service are on the market, and they are acquired at different moments from different budgets. The selection between them comes first, before any provider is approached.
Three forms and the question each one answers
The pattern in a live deal is usually a two-week exclusivity window, a data room that opens on day four, and a code review that starts on day nine. No amount of technical depth survives that sequence, which is why provider selection is really engagement-shape selection.
BD Emerson's comparison of technical due diligence firms lists the attributes that separate providers: who actually reads the repository, whether the firm fits a one to three week deal window, how deep the scope runs across architecture, security, the engineering team, scalability and IP, whether the report can be read by an investment committee, and what happens to the findings after close. The same attributes divide the types of engagement as cleanly as they divide the firms.
| Attribute | Pre-offer screen | Full technical diligence in exclusivity | Integrated diligence across technology, commercial and operations |
|---|---|---|---|
| Question it answers | Whether the estate contains a reason not to bid | What the technology is worth, what it costs to own, and what breaks first | How technology, commercial and operational findings change the deal thesis together |
| Who does the work | One senior engineer reading the data room and external footprint | A small team reading code, architecture, tickets and interviewing engineers | A multi-track team with technology as one workstream among several |
| Typical window | Three to five working days | Ten working days to four weeks | Four to six weeks, coordinated with financial and legal tracks |
| Report output | A proceed, caution or walk call | A ranked findings list with remediation ranges for the model | An integrated investment story with synergy targets attached |
| Post-close follow-through | None unless you commission the next engagement | Optional remediation and integration quote | Value creation office carries targets past close |
| Fee construction | Fixed fee, often credited against a later full diligence | Fixed fee quoted before work begins, tiered by complexity | Success fee or retainer, sometimes both |
| Failure mode | Screen finds nothing because the data room was thin | Report arrives after the investment committee has met | Technology findings are diluted by the other tracks |
The table is the decision. The checklist below tests whether your chosen form is being executed against your deal.
Before the data room opens
You have specified the decision the diligence is meant to change. If the answer is no, cease the process.
You know whether your own team or a supplier you have previously identified can maintain the target's custom software. MEV's guide reports that most serious findings trace back to missing technology governance, which surfaces as undocumented architecture and knowledge that left with the people who built the system. The question is whether that knowledge resides with a specific person you can hire or engage.
The provider has identified the engineers who will read the repository. Ask for individuals.
The scope covers architecture, security, the engineering team, scalability and IP ownership. A review that skips the team or the IP chain of title omits two of the most expensive surprises from inspection, as BD Emerson's comparison puts it.
You have agreed the timetable against the deal calendar, including the exclusivity window. DFIN's guide warns that the average merger takes five to six months and the technology track occupies a fraction of it.
When the interim report lands
Findings are ranked by cost and deal impact. A long appendix without a ranked summary forces the committee to do the analyst's job.
Remediation estimates are ranges tied to specific drivers. The drivers matter because they tell you what to negotiate.
The team section is as deep as the code section. Key-person dependency is a finding.
Open-source licensing and IP ownership have been checked. Ansarada's technology due diligence article lists open-source components and software licensing among the items that belong in the review, as a licence problem can limit development after close.
The report says what it did not examine. A silence is a gap.
When the model is rebuilt
The remediation estimate has entered the model as a line. If it is a paragraph, the number is not real.
Integration cost is separated from run cost. One is a one-time charge, the other changes the target's operating expense after completion.
The synergy case has been tested against the technology. Roland Berger's tech due diligence practice reports that 60% of synergies are directly or indirectly dependent on technology, which means a synergy number built without the technology track is a number built on an assumption.
The price has moved, or the deal thesis has been confirmed with evidence. Either outcome is a result. A diligence that changes no outcome was acquired too late.
After completion
The report has become a first-hundred-days plan. The findings should convert into remediation and integration actions with owners and dates.
The key-person dependencies have been mapped to specific replacements or retention terms. DFIN's technical due diligence guide lists key-person dependency in the development team as a pitfall, and the pitfall is that the replacement cost lands after close.
The security uplift is scoped to what the group's contracts require. Dead Simple Computing's technology due diligence page describes post-completion work as a security uplift to the group's contractual requirements, which is a different scope from a generic hardening programme.
The estate's licensing position has been normalised. Open-source obligations and third-party licences do not disappear when the deal closes.
The way the fee is set predicts how the process will break
A pre-offer screen acquired from a firm that also sells remediation has an incentive to find remediation. The honest handling is disclosure up front, as BD Emerson puts it, plus remediation estimates the buyer can take to any provider. A full diligence performed for a fixed fee quoted before work begins has a different incentive: to finish inside the window. An integrated diligence service acquired as part of a larger advisory relationship has a third: to keep the technology track from contradicting the commercial story.
Not one of these is dishonest. They are the incentives that come with the shape of the engagement, and they are visible before you sign.
Sources
- Best Technical Due Diligence Firms in 2026 | BD Emerson
- Technical Due Diligence | DFIN
- Technical Due Diligence Guide: Process, Checklist & Red Flags | MEV
- Technology Due Diligence In M&A | Ansarada
- Tech due diligence | Roland Berger
- Technology Due Diligence & PE Deal Assurance | Dead Simple Computing
Run through this
- Name the specific decision the diligence is meant to change.
- Confirm if the target's custom software can be maintained by your team or a known supplier.
- Obtain the names of the specific engineers who will read the repository.
- Verify the scope covers architecture, security, the engineering team, scalability and IP ownership.
- Agree the timetable against the deal calendar and exclusivity window.