A post-merger IT integration that fails to establish operational capability within the first 100 days wastes time that will be nearly impossible to make up later. After the closing of an acquisition, every day counts twice as much—for employees as well as for customers, who are closely watching to see if orders, deliveries, and invoices continue to process smoothly. According to KPMG, it is precisely these first 100 days after closing that lay the foundation for the overall success of the integration (KPMG, 10/2024).
Post-merger IT integration primarily establishes the ability to take action and a robust plan within the first 100 days after closing; full system consolidation takes significantly longer. According to KPMG (October 2024), cultural integration, compliance, and visible synergies are among the key challenges. The process begins with Identities, Networks, and Access Rights.
The Five Key Areas of Post-Merger IT Integration
KPMG identifies five key areas that determine the success of an integration: product integration, functional integration, IT integration, cultural integration, and risk management (KPMG, 10/2024). IT integration is rarely the most prominent focus here, but it provides the foundation on which the other four can function. It’s difficult to build a shared culture when two workforces are still using separate email systems and separate file storage systems and therefore rarely interact in their day-to-day work.
Without properly functioning identities and access rights, it is impossible to build a shared culture or demonstrate compliance with regulations. According to KPMG, the key challenges lie in cultural integration, adherence to compliance requirements, and making synergies visible (KPMG, 10/2024). Synergies that do not become apparent within 12 to 24 months lead, according to KPMG, to rising costs and inefficiencies (KPMG, 10/2024).
According to KPMG, costs and inefficiencies rise after the initial period needed to realize synergies following an acquisition.
KPMG, October 2024
Regulatory approvals also need to be addressed during this early phase. Those who wait to obtain them until the IT integration is already underway risk making technical decisions that will later have to be reversed to comply with regulatory requirements. The article describes how thoroughly the target company’s IT landscape is examined even before the deal is signed. Technical Due Diligence in Acquisitions: What the Code Reveals About the Company.
What IT integration specifically entails during the first 100 days
Five areas determine whether a company is technically capable of operating after an acquisition.
| Area | What the First 100 Days Are All About |
|---|---|
| Identities and Directory Services | A shared access model to ensure that no one is listed twice or not at all |
| Networks | Secure connection between both locations without compromising the existing security architecture |
| ERP Environments | Decide which system will remain the primary one for the time being, and establish a temporary solution for the rest |
| Licenses | Avoiding duplicate costs and unresolved usage rights beyond the effective date |
| Data Protection Responsibilities | Assignment of responsibility for specific categories of personal data |
These five areas cannot be addressed one after another; they run in parallel and influence one another. A common access model, for example, is a prerequisite for ensuring that data protection responsibilities can be assigned without any overlap. Where both organizations process the same data, Article 26 of the GDPR, which requires joint controllers to enter into a written agreement regarding the allocation of responsibilities.
One risk is often overlooked in the rush. If a key person leaves the acquired company shortly after the closing, the only person with a thorough understanding of the established system landscape is often lost—a key-person risk that is particularly high during the integration phase.
Who Leads IT Integration During the First 100 Days
Two IT organizations that are just getting to know each other rarely clarify responsibilities on their own. Without designated leadership with decision-making authority, each team prefers to continue negotiating its own solution rather than agreeing on a joint one, and that is exactly what takes up the most time in the first 100 days.
A common pattern is to have existing executives from both organizations manage the IT integration on the side, in addition to their day-to-day business. This works for individual decisions, but fails to ensure continuity as soon as multiple issues are being addressed simultaneously—such as identity management, networks, and ERP issues—in parallel rather than sequentially.
Having a single person with decision-making authority across both sides significantly reduces these friction losses. This person doesn’t have to answer every technical detail themselves, but any question that gets stuck between the teams ultimately ends up with them and is decided there, rather than remaining unresolved for days. The article shows what it costs to bring in such an external resource Interim CTO: Costs, Duration, Expectations.
It is unrealistic to expect full system consolidation to be completed in 100 days. The focus during this time is on maintaining the ability to act and developing a robust plan for the coming months, not on having a fully merged system.
Ready to take action from day one
For the first 100 days, a concrete IT roadmap can usually be drawn up within a few days.
Frequently Asked Questions
What should be included in the first 30 days?
During the first 30 days, an overview of both IT environments is developed, including responsible parties, critical dependencies, and acute security risks. At the same time, a common identity access model is established, as nearly all subsequent integration steps depend on it. Regulatory reporting requirements and approvals are also reviewed during this period—not just once a deadline is already in effect. Ideally, by the end of the first 30 days, there will be a prioritized list of outstanding risks, not just a list of good intentions.
Should we run the two systems in parallel or consolidate them immediately?
During the first 100 days, running systems in parallel is almost always the safer choice. Immediate consolidation of ERP landscapes or core systems under time pressure significantly increases the risk of outages and data loss. The actual consolidation follows once the plan for the first 100 days is in place and can be thoroughly tested. Premature consolidation, undertaken solely to quickly signal success, almost always backfires in the form of outages that subsequently erode trust.
Who is leading the IT integration?
A joint team from both companies works most effectively under a single technical leader with decision-making authority. Without this single point of responsibility, many issues get bogged down between two IT organizations that are not yet familiar with each other and do not grant each other decision-making authority. Filling this role with an external hire can often be done more quickly and impartially than an internal promotion might be in the midst of such a transition.
The first 100 days of a post-merger IT integration determine whether a company remains operational after the acquisition or gets bogged down in questions of responsibility. During this phase, torck takes on the technical leadership role, with its own development teams in Maxhütte-Haidhof, Vienna, and Rabat, rather than simply outlining an integration plan that others must implement. The contracting party is the German company torck GmbH. Anyone planning IT integration following an acquisition can take the first steps in a Initial Consultation .
This article refers to laws and regulations to put technical decisions in context. It is not legal advice. Whether and how a rule applies to your company is a question for your legal department or a law firm.
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