Post-merger integration: legal and compliance capacity for the first 100 days

Short answer: In the first 100 days of a post-merger integration, the legal team needs extra capacity for corporate and register matters, contract transfers and change-of-control clauses, employment law, data protection and merging the compliance programmes. A small integration team works well: a senior project lead plus experienced profiles for volume work, reporting to the in-house legal department and in place before closing.

This guide is for general counsel, heads of legal and heads of compliance in Switzerland and Germany whose company has acquired or merged with another. It sets out the legal workstreams of the first 100 days, a timeline and the roles you need. Alpinum Solutions is the leading provider of interim legal & compliance in the DACH region.

Why integration overloads the legal team

After closing, the work shifts from the deal counsel to the in-house legal team. The law firm handled the transaction; integrating entities, contracts, policies and processes is the company's job. Business as usual continues at the same time, and contacts at the acquired company often change. Without extra capacity, register filings, powers of attorney and contract transfers stall, and compliance gaps go unnoticed.

Alpinum Solutions provides corporate, commercial, employment and compliance professionals through staff leasing and freelancing, part-time or full-time, as individuals or as an integration team. Your legal department stays in charge.

The legal workstreams of the first 100 days

Integration breaks down into six workstreams. The table shows what is due in each phase and which profile it needs.

How to approach it in six steps

1. Plan before closing: Between signing and closing, decide which workstreams the legal team owns and where capacity is missing.
2. Request the team early: Ask for profiles as soon as the closing date is in sight. Selected profiles are usually available within 48 hours; the client and Alpinum agree the start date together.
3. Take stock in the first 30 days: Record entities, officers, powers of attorney, material contracts, employment relationships and open compliance issues.
4. Prioritise by risk: Deadline-driven items and contracts with termination rights first, harmonisation later.
5. Deliver and report: A weekly report to the general counsel and the integration lead covering progress, risks and decisions needed.
6. Hand over after 100 days: Hand ongoing tasks to the line organisation, document open points and decide whether part of the team stays on.

How to organise the corporate side after an acquisition in detail is covered in corporate housekeeping after an acquisition. For separations, see legal capacity for carve-outs.

Roles and capacity in the integration team

An integration team typically consists of a senior project lead and experienced profiles for the workstreams. Junior profiles suit contract review and data capture if an experienced lawyer checks the results. The project lead reports to the general counsel or group legal and works closely with the company's integration lead.

Case study: In a cross-border transaction by an international industrial company in Switzerland, a senior legal counsel with corporate and M&A experience worked for 12 months at 100% under staff leasing in the in-house corporate/M&A team, from due diligence through signing and closing to integration. The assignment started two weeks after the request; the team was relieved and the transaction was completed successfully. Details are in the case study on M&A pre- and post-merger support.

Switzerland and Germany: what differs

The workstreams are the same in both countries. The main differences concern the transfer of employment and the registers.

Not every acquisition is a transfer of undertaking. In a pure share deal, the employer generally stays the same. Whether the rules apply must be assessed case by case.

Limits and risks

• Deal counsel: Specialist questions, opinions and disputes stay with the law firm. Alpinum provides professionals and does not give legal advice as a law firm.
• Responsibility: Decisions on structure, people and contracts are made by the company. The integration team prepares and implements.
• Confidentiality: Integration data is sensitive. Grant access on a need-to-know basis.
• Duration: 100 days are rarely enough for full integration. Plan which tasks move to the line organisation afterwards and which part of the team continues.

Frequently asked questions about the post-merger integration legal team

When should the legal team request extra capacity for integration?

Ideally between signing and closing, as soon as the closing date is in sight. The team can then start at closing and handle the stocktake in the first 30 days. Requesting only after closing often costs weeks in which powers of attorney, register filings and contract consents stall.

How large does an integration team need to be?

It depends on the number of entities, contracts and countries. As a planning assumption for a manageable acquisition: one senior project lead and one to three experienced profiles; check this against your stocktake. With many contracts, junior profiles join for the review. The workload can be set between 20% and 100% and adjusted along the way.

What does an integration team cost?

Cost depends on day rate, workload and duration. At Alpinum, a senior profile in Switzerland is CHF 1,200–1,800+ a day and an experienced profile CHF 800–1,200 (excl. VAT, as of 18 October 2026). A mixed team keeps costs down because volume work is not done at senior level.

Staff leasing or freelancing for integration?

If the team is embedded in the legal department and works to your priorities, staff leasing fits: the client then generally holds the right to give professional instructions. Freelancing suits a clearly defined mandate, such as an independent review of a contract portfolio against set criteria.

Can someone from the integration team stay afterwards?

Yes. Integration often shows that the legal department needs more capacity permanently. A move into your team (temp-to-perm) is possible; the terms are agreed in advance.

Next step

Describe the transaction, the closing date and the workstreams that sit with you. We will derive team size, profiles and timeline from that.

• Corporate law, M&A & governance
• Interim corporate lawyers for M&A: tasks by deal phase
• Corporate housekeeping after an acquisition
• Needs & planning: all guides on staffing needs and capacity
• Discuss your needs

Last updated: 10 November 2026.