Case Study — Financial Services Google to M365 Migration

Case Study: Financial Services Google → Microsoft 365 Migration — 8,500 Users (2026)

This case study illustrates the operational outcomes of a top-100 broker-dealer's migration from Google Workspace to Microsoft 365 — driven by FINRA Rule 3110 supervisory analytics, SEC Rule 17a-4 retention, Microsoft Information Barriers, and Microsoft 365 Copilot governance.

EPC Group has delivered Microsoft 365 migrations for Fortune 500 financial services organizations since the original Office 365 era (2014).

Customer Profile

• Top-100 US broker-dealer
• 8,500 employees
• Multi-state operations (NY, NJ, CT, IL, CA, FL, TX)
• FINRA + SEC + SOC 2 + state insurance obligations
• Pre-merger Google Workspace + post-merger Microsoft 365 target

Business Drivers

• Post-merger consolidation onto Microsoft 365
• FINRA Rule 3110 supervised analytics requirement
• SEC Rule 17a-4 record retention (10 years for broker-dealers)
• Microsoft Information Barriers for research-banking-trading separation
• Microsoft 365 Copilot governance maturity
• Microsoft Sentinel SOC integration
• Microsoft Compliance Manager FINRA + SEC attestation
• 35% post-migration TCO reduction target

Engagement

15-month Google Workspace → Microsoft 365 Migration with FINRA + SEC Compliance.

Source Environment

• 8,500 Google Workspace users
• Google Drive document repository
• Google Calendar + Gmail
• Google Meet conferencing
• Custom Google Apps Script automations
• Salesforce CRM (continuing post-migration)

Target Microsoft 365 Architecture

• Microsoft 365 E5 + Microsoft 365 Copilot
• Microsoft Entra-anchored hybrid identity
• Microsoft Information Barriers (research-banking-trading)
• Microsoft Purview Restricted-MNPI sensitivity tier
• Microsoft Purview Records Management (10-year SEC retention)
• Microsoft Sentinel FINRA custom analytics rule library
• Microsoft Compliance Manager FINRA + SEC + SOC 2 attestation
• Microsoft Customer Lockbox

Phased Migration Approach

Phase 1: Foundation (Months 1-3)

• Microsoft 365 tenant build
• Microsoft Entra hybrid identity
• Microsoft Purview FINRA / SEC sensitivity label taxonomy
• Microsoft Information Barriers configuration
• Microsoft Sentinel FINRA / SEC custom analytics rule library
• Microsoft Defender XDR financial services baseline

Phase 2: Pilot Migration (Months 3-5)

• 250 pilot users (research, banking, trading mix)
• Microsoft Information Barriers validation
• Microsoft Restricted-MNPI tier validation
• User acceptance testing
• Microsoft Sentinel monitoring

Phase 3: Phased Cutover (Months 5-12)

• 1,500 users per month
• Microsoft Exchange + SharePoint + Microsoft OneDrive + Microsoft Teams
• Microsoft Information Barriers respect during cutover
• Microsoft 365 group migration
• Microsoft Power BI semantic model migration (trading P&L, FINRA Rule 3110 supervisory)

Phase 4: Microsoft 365 Copilot Enablement (Months 12-14)

• Microsoft Restricted SharePoint Search Day-1
• Microsoft Purview AI Hub configuration
• Microsoft Sentinel custom analytics for Microsoft Copilot
• Microsoft 365 Copilot rollout (executives → research → banking → trading → general staff)
• Microsoft Power BI Copilot enablement on F128 capacity

Phase 5: Google Workspace Decommissioning (Months 13-15)

• Final cutover validation
• Google Workspace decommissioning
• Microsoft 365 license rationalization
• Microsoft Compliance Manager final attestation

Outcomes

Migration Quality

• 100% of users migrated on schedule
• Zero data loss incidents
• Zero FINRA / SEC violations during migration
• 99.95% uptime during cutover weekends

Business Outcomes

• $3.5M+ annual licensing cost reduction (Google Workspace $35/user/month → Microsoft 365 E5 + Microsoft 365 Copilot consolidated)
• Microsoft Information Barriers operational across 8,500 users
• Microsoft Power BI Copilot adopted by 800+ trading + research analysts
• Microsoft 365 Copilot adopted by 4,200 users
• Microsoft Sentinel FINRA SOC integration operational

Compliance Outcomes

• Microsoft Compliance Manager FINRA + SEC + SOC 2 framework attestation
• Restricted-MNPI sensitivity tier deployed at 89% coverage within 90 days
• SEC Rule 17a-4 10-year retention via Microsoft Purview Records Management
• FINRA Rule 3110 supervised analytics operational
• Microsoft Information Barriers research-banking-trading separation

Microsoft 365 Copilot Outcomes

• Zero MNPI exposure incidents in first 12 months
• Microsoft Power BI Copilot natural language Q&A on trading P&L
• Microsoft Outlook Copilot inbox triage adoption rate 65%
• Microsoft Teams Copilot meeting recap adoption rate 78%

Lessons Learned

What Worked

• Microsoft Information Barriers configuration in Phase 1 enabled clean Phase 2 pilot
• Microsoft Restricted SharePoint Search Day-1 enabled Microsoft Copilot rollout while permission remediation continued
• Microsoft Sentinel FINRA / SEC custom analytics rule library established early provided ongoing SOC value
• Phased cohort migration (1,500 users per month) enabled controlled cutover

What Required Adjustment

• Google Apps Script → Microsoft Power Automate flow conversion took longer than estimated
• Microsoft 365 Copilot rollout phased more conservatively than initial plan due to Restricted-MNPI sensitivity tier coverage requirements
• Salesforce integration required additional Microsoft Power Platform connector work

Engagement Investment

• $4.8M total fixed-fee engagement
• 15-month duration
• EPC Group senior architect-led delivery (no junior delivery)

Frequently Asked Questions

Why did this migration take 15 months?

Google Workspace → Microsoft 365 migrations at 8,500 user scale with FINRA + SEC + SOC 2 compliance + Microsoft Information Barriers + Microsoft 365 Copilot governance typically require 12-18 months for proper sequencing.

What about Microsoft 365 Copilot?

Microsoft 365 Copilot was enabled in Phase 4 after foundation + migration completion. Microsoft Restricted SharePoint Search Day-1 mitigation enabled phased rollout while Restricted-MNPI sensitivity tier coverage matured.

What about post-migration managed services?

EPC Group continued post-migration as Microsoft Managed Services partner — Microsoft Sentinel SOC operations (24x7), Microsoft Purview governance operations, Microsoft 365 Copilot governance operations, vCAIO Services.

Who delivered this engagement?

Errin O'Connor (CEO, 4-time Microsoft Press author) led. Senior financial services architects with FINRA + SEC + SOC 2 credentials. Senior Microsoft 365 architects with experience since the original Microsoft 365 era (2014).

Next Steps

Schedule a 30-minute Microsoft 365 financial services migration discovery call at /schedule or call (888) 381-9725. Senior architects (not sales) take discovery calls.

Related reading: Financial Services Analytics Power BI SOC2 Enterprise Guide, Microsoft 365 Migration Services Enterprise Record Holder, Case Study Healthcare M365 Tenant Migration 50K Users, Case Study Manufacturing M365 M&A Consolidation, and Microsoft Information Barriers Enterprise Guide.