Post-Merger Integration Checklists and Templates

This article consolidates the practical resources you need during an actual integration. These aren't just reading material. They're working documents you can use, adapt, and apply to your next deal.

According to Eight International, only 40% of acquirers use structured integration playbooks despite their proven benefits. Companies with dedicated integration leaders achieve 75% success rates. The difference often comes down to having the right frameworks and checklists in place.

Below you'll find decision frameworks, audit checklists, timeline templates, and communication scripts. Use them as starting points and adapt them to your situation.

This article is adapted from Chapter 8 of The Roll-Up Integration Playbook, our free guide to post-merger technical integration.

Integration Level Decision Framework

Use this framework when deciding how deeply to integrate each acquisition. For the full context on High/Medium/Low-Touch integration, see How to Decide the Right Integration Level for Each Acquisition.

Strategic Questions

QuestionHigh-TouchMedium-TouchLow-TouchWhat's our strategic intent?Unified platform, single brandCapability or market acquisitionTesting new vertical, short holdHow does this fit our model?Scale play, synergy-focusedRelated but distinct businessesPortfolio play, financial returnsWhat's our brand strategy?Single platform brandHouse of brands, endorsed brandsSeparate brands

Operational Questions

QuestionHigh-TouchMedium-TouchLow-TouchHow large is this acquisition?Small tuck-in (<20% of platform)Significant (20-50% of platform)Any sizeHow do their systems compare?Clearly inferiorRoughly equivalent or mixedAnySignificant customer overlap?YesSomeNoSpecialised operational needs?NoYes, some specialist toolsYes, highly specialised

Risk Questions

QuestionHigh-TouchMedium-TouchLow-TouchRisk tolerance?Higher (can absorb disruption)ModerateLowKey person dependency?LowModerateHighCurrent business situation?Stable, off-peakNormal operationsCritical period, peak season

How to use it: If most answers fall in one column, that's likely your integration level. Mixed answers suggest Medium-Touch with flexibility on specific systems.

Integration Audit Checklist

Complete this before starting any migrations. For the full discovery process, see The Post-Acquisition Integration Audit.

System Inventory

• All software applications documented (cloud, installed, legacy)
• Hardware assets inventoried (servers, network, devices)
• Integrations and data flows mapped
• Contracts, renewal dates, and costs captured
• Admin access and ownership identified
• Shadow IT discovered (personal accounts, undocumented tools)
• "Closet servers" and on-premise systems found

Security Baseline

• Privileged access audit completed
• Shared passwords changed
• Former employee accounts disabled
• MFA enabled on email and critical systems
• Endpoint protection verified on all devices
• Backups confirmed and test restore completed
• Network perimeter reviewed

Department Interviews

• Operations head interviewed
• Sales/commercial head interviewed
• Finance head interviewed
• HR head interviewed
• Customer service lead interviewed
• Key knowledge holders identified
• Workflows and workarounds documented
• Pain points and quick win opportunities captured

Data Quality Assessment

• CRM data sampled and assessed
• Finance data reviewed
• HR/employee data checked
• Duplicate rate estimated
• Completeness assessed
• Data cleanup scope defined

Stakeholder Mapping

• Champions identified
• Potential resisters identified
• Key knowledge holders flagged
• Decision makers mapped
• Communication plan drafted

Governance

• Integration lead assigned
• Decision rights documented
• Escalation path defined
• Communication cadence agreed
• Success criteria defined and documented

First 100 Days Timeline

This is typical phasing for a medium-complexity integration. For the full execution playbook, see The First 100 Days After an Acquisition.

Day 1

• Security baseline established (or email migration if Day 1 cutover)
• Communication sent to acquired team
• Integration team introduced
• Immediate access and permissions sorted

Days 1-30: Stabilisation

Week 1:

• Complete system inventory
• Begin department interviews
• Establish financial bridge for reporting
• Identify quick wins

Weeks 2-3:

• Complete department interviews
• Assess data quality in detail
• Map stakeholders
• Introduce cross-company counterparts
• Deliver quick wins

Week 4:

• Finalise integration roadmap
• Detailed migration plans drafted
• Plans reviewed and approved
• Training approach agreed

Days 31-60: Early Execution

• Email/identity migration (if not Day 1)
• CRM migration begins
• Data cleanup in progress
• Training preparation underway
• Weekly status updates established

Days 61-90: Core Execution

• CRM migration complete
• Finance/ERP migration (aligned to fiscal calendar)
• HR migration
• Training delivered
• Adoption monitoring active

Days 90+: Stabilisation

• Hypercare support active (2-4 weeks)
• Adoption metrics reviewed
• Issues addressed
• Knowledge transfer completed
• Lessons learned captured

System Migration Sequencing Guide

This is the typical order and timing. For detailed guidance on each system type, see System Migration After Acquisition.

SystemTypical TimingDependenciesKey ConsiderationsEmail/IdentityDays 1-30NoneCan be Day 1 for security. Watch for Conversion Trap (Google to Microsoft).CRMDays 30-60Email completeHighest sales disruption risk. Budget time for data cleanup. 8-12 weeks typical.Finance/ERPDays 45-90Financial bridge in placeAlign to fiscal calendar. Parallel running mandatory. 12-20 weeks typical.HR/PayrollDays 30-60None (can parallel with CRM)Align to payroll cycles. Test thoroughly before go-live.OperationalDays 60-90+Core systems stableConsider API integration vs full migration. May defer or keep separate.

When to deviate:

• Urgent finance reporting needs? Move ERP earlier.
• Broken CRM losing deals? CRM becomes priority.
• Complex operational systems? May defer or keep separate with API integration.

Training & Adoption Checklist

Use this for each major system migration. For the full adoption playbook, see Why Systems Don't Fail — Adoption Fails.

Before Go-Live

• Training approach defined (live, recorded, documentation)
• Role-based training content created
• Digital champions identified and briefed
• Training schedule communicated
• Quick reference guides prepared
• Support channels established

Training Delivery

• Champions trained first (deeper training)
• Role-based sessions delivered
• Hands-on practice included
• Questions documented for follow-up
• Recordings available for reference

Go-Live

• Go-live communication sent
• Support team ready
• Champions available to help peers
• Escalation path clear
• Adoption tracking active

Hypercare (Weeks 1-4)

• Daily check-ins with champions
• Adoption metrics reviewed weekly
• Issues addressed promptly
• Additional training for struggling users
• Workarounds documented and addressed
• Feedback gathered

Post-Hypercare

• Ongoing support transitioned
• Refresher training planned
• Process refinements implemented
• Success celebrated

Stakeholder Communication Templates

Pre-Migration Announcement

Subject: Upcoming changes to [System Name]

As part of our integration, we'll be moving to [new system] over the coming weeks. Here's what you need to know:

What's changing: [Brief description]

Timeline: [Key dates]

What you need to do: [Any preparation required]

Training: [When and how]

Questions? Contact [name/channel]

We'll keep you updated as we progress. Thanks for your patience during this transition.

Go-Live Announcement

Subject: [System Name] is now live

As of today, [new system] is live. Here's what you need to know:

Getting started: [Link to guide or key first steps]

Support: [How to get help]

Known issues: [Any issues being worked on]

Thanks to everyone who helped prepare for this. If you run into any problems, reach out to [contact].

Weekly Status Update (Internal)

Integration Status: Week [X]

Completed this week:

• [Item 1]
• [Item 2]

Planned for next week:

• [Item 1]
• [Item 2]

Issues/Risks:

• [Issue and status]

Decisions needed:

• [Decision required and by whom]

Glossary

Chart of Accounts (CoA): The structure of categories used to record financial transactions. Mapping between different CoAs is a key part of finance integration.

Conversion Trap: The problem of Google Docs/Sheets breaking when converted to Microsoft Office formats during migration, especially files with complex formulas or scripts.

Digital Champion: A respected team member who supports adoption by helping peers learn new systems.

High-Touch Integration: Full system consolidation including brand unification. The acquired company is fully absorbed into the platform.

Hypercare: A period of elevated support (typically 2-4 weeks) immediately after go-live.

Low-Touch Integration: Minimal integration, typically financial reporting only. Systems and brand remain separate.

Medium-Touch Integration: Back-office system consolidation (CRM, ERP, HR) while preserving separate customer-facing brands.

Minimum Viable Integration (MVI): Doing enough integration to capture the value you need, without over-engineering or over-disrupting.

Parallel Running: Operating old and new systems simultaneously during transition to verify accuracy before cutover.

Shadow IT: Technology used within the business that wasn't officially provisioned or documented, such as personal cloud storage or spreadsheet-based tools.

Sunset Policy: Defined criteria for when a legacy system must be replaced, used when keeping systems separate temporarily.

Key Takeaways

• Use decision frameworks, not gut feel. The integration level framework helps you make consistent, defensible decisions across acquisitions.
• Don't skip the audit. Discovery done well saves multiples in avoided surprises and rework.
• Follow a timeline, but adapt it. The 100-day framework is a guide, not a rigid schedule. Let business priorities drive adjustments.
• Sequence migrations deliberately. Order matters. Dependencies and business priority should drive your sequence.
• Adoption is where integrations succeed or fail. Technical migration is only half the job. Plan for training and change management from the start.

Get the Full Playbook

This article compiled the key checklists and templates. For the complete guide, including the strategic context behind each framework, download The Roll-Up Integration Playbook.

Download the Playbook

About PMI Stack

PMI Stack helps small-to-mid cap roll-ups unify systems, data, and workflows across their acquired companies. We specialise in the technical side of post-merger integration: data migration, system consolidation, and the change management that makes new tools stick.

If you're planning an integration and want to talk through your specific situation, book a free discovery call.

Statistics cited from Eight International. For the full research compilation, see 50+ Post-Merger Integration Statistics (2026).