M&A HR Project Manager

Top Stack; Newtown Square (Delaware County); On-site; USD 65,000 - 95,000; Part time

Job summary

Top Stack is seeking an experienced M&A Integration/HR Project Manager to support acquisition activity, focusing on payroll, benefits, and 401(k) integration. Your time will center on active deals and related HR system changes across the company.

In this role, you will coordinate with HR, payroll, finance, and benefits providers, consolidate data, and ensure accurate conversions and timely project milestones while supporting other HR projects as needed.

Qualifications

• Hands-on M&A integration experience, HR/payroll/benefits focus.
• 401(k) integration experience with plan mergers and data transfers.
• Experience integrating payroll and benefits programs.
• Advanced Excel skills (lookups, pivot tables, data comparison, large datasets).

Responsibilities

• Support integration of acquired companies' payroll, benefits, and 401(k) plans.
• Consolidate employee, payroll, and benefits data from acquired entities into a single view.
• Coordinate with HR, payroll, finance, benefits carriers, 401(k) providers, and the acquired company's teams to keep integration timelines on track.
• Review and verify data for accuracy before and after conversion, using Excel-based reconciliations and validation checks.
• Identify discrepancies, track them to resolution, and document findings.
• Help maintain integration checklists, trackers, and status updates.
• Support payroll and benefits process improvements and system changes.
• Assist with HCM system updates, configuration changes, testing, and rollouts.
• Help with audits, data clean-up, and other special projects as needed.

Skills

M&A integration

401(k) integration

Payroll integration

Advanced Excel

Data consolidation

Attention to detail

Clear communication

Time management

Tools

Workday

UKG

ADP

Paylocity

Job description

Our client is looking for an experienced M&A Integration/HR Project Manager to support acquisition activity, with a focus on payroll, benefits, and 401(k) integration. Your time will go primarily to active M&A projects. When there is no active deal, you will support other initiatives across the company, mainly in payroll, benefits, and HCM change projects.

What You'll Do

M&A Integration (primary focus)

• Support the integration of acquired companies' payroll, benefits, and 401(k) plans
• Consolidate employee, payroll, and benefits data from acquired entities into a single view
• Coordinate with HR, payroll, finance, benefits carriers, 401(k) providers, and the acquired company's teams to keep integration timelines on track
• Review and verify data for accuracy before and after conversion, using Excel-based reconciliations and validation checks
• Identify discrepancies, track them to resolution, and document findings
• Help maintain integration checklists, trackers, and status updates

Payroll, Benefits & HCM Projects (when M&A work is light)

• Support payroll and benefits process improvements and system changes
• Assist with HCM system updates, configuration changes, testing, and rollouts
• Help with audits, data clean-up, and other special projects as needed

What You Bring

Required

• Hands-on M&A integration experience, ideally on the HR, payroll, or benefits side
• 401(k) integration experience (plan mergers, data transfers, provider transitions, or similar).
• Experience integrating payroll and benefits programs
• Advanced Excel skills (lookups, pivot tables, data comparison, and large-dataset handling)
• Proven ability to consolidate, coordinate, review, and verify data across multiple sources
• Strong attention to detail and a habit of double-checking your work
• Clear communicator who can work with multiple stakeholders and keep projects moving
• Ability to work independently and manage your own time in a part-time role

Preferred

• Experience with HCM platforms (e.g., Workday, UKG, ADP, Paylocity, or similar)
• Background in HR operations, payroll, benefits administration, or HR consulting
• Familiarity with compliance considerations in benefits and retirement plans