8,500 Users. Google to Microsoft 365. 90-Day Audit Clock.
How a financial services firm migrated its entire workforce from Google Workspace to Microsoft 365 — and passed a SOC 2 audit before the ink was dry.
Case Study Summary: A mid-market financial services firm with 8,500 employees needed to migrate from Google Workspace to Microsoft 365 — with a SOC 2 Type II audit scheduled in 90 days. EPC Group completed the migration in 12 weeks with 100% data integrity, all 23 custom automations rebuilt, and the client passed their audit with zero findings. Post-migration, 2,000 users were deployed on Copilot for Microsoft 365, delivering a measured 40% productivity improvement.
The Bet That Changed Everything
The new CTO arrived on a Monday and called an all-hands by Wednesday. “We are a Microsoft shop now,” she announced to a room full of Google loyalists. The groans were audible. Google Workspace had been the firm's backbone for seven years. Traders lived in Gmail. Analysts built models in Google Sheets. The compliance team ran workflows through custom Google Apps Script automations that nobody fully understood anymore.
But the CTO had done her homework. The firm's biggest competitors had deployed Copilot for Microsoft 365 and were already seeing measurable productivity gains — AI-generated client reports, automated meeting summaries for compliance documentation, intelligent email drafting that cut response times in half. In financial services, where time is literally money, falling behind on AI adoption was not an option.
There was just one problem. The firm's SOC 2 Type II audit was scheduled in 90 days. Auditors would examine their technology controls, data security practices, and change management processes. Migrating an entire platform in the middle of an audit cycle was, in the words of the Chief Compliance Officer, “insane.”
The CTO did not blink. “Find me a partner who has done this before. Someone who understands SOC 2. Someone who will not lose a single file.”
The Challenge: Platform Change Under Regulatory Pressure
This was not a simple email migration. Financial services firms operate under some of the most scrutinized regulatory environments in any industry. Every piece of data has retention requirements. Every access event is logged. Every change must be documented, approved, and auditable. Migrating 8,500 users from one cloud platform to another — while maintaining continuous SOC 2 compliance — is the technology equivalent of changing the engine on an airplane while it is flying.
The complexity ran deeper than most people realized. Seven years of Google Workspace had created an ecosystem. Traders had custom Gmail filters that triggered automated workflows. The research team had Google Sheets with complex Apps Script macros that pulled live market data. The compliance team had built an entire review-and-approval workflow in Google Forms that handled 200+ regulatory submissions per month. None of these would work after migration — they all needed to be rebuilt from scratch.
8,500 Employees
Traders, analysts, portfolio managers, compliance officers, and support staff — all deeply embedded in Google Workspace for 7 years
45 TB of Data
Gmail archives going back 7 years, 45 TB of Google Drive files, thousands of shared drives, and Google Vault retention data
SOC 2 Audit in 90 Days
Type II audit covering Security, Availability, and Confidentiality trust criteria — auditors would examine migration change management
23 Custom Automations
Google Apps Script workflows handling trading notifications, compliance approvals, client reporting, and regulatory submissions
47 Third-Party Integrations
Bloomberg terminal feeds, Salesforce CRM, compliance monitoring tools, and market data providers — all connected via Google APIs
Data Classification
Restricted, Confidential, Internal, and Public data classifications — each with different retention and access requirements under SEC regulations
The Stakes: A Regulatory Audit That Could Not Wait
The SOC 2 audit was not negotiable. Financial services firms cannot reschedule audits because their IT team decided to migrate platforms. The auditors were coming in 90 days whether the migration was complete or not. If the migration was mid-flight when auditors arrived, the firm would need to demonstrate continuous control coverage — proving that security, availability, and confidentiality controls were maintained throughout the transition.
A failed audit would trigger client notification requirements. The firm managed $14 billion in assets under management across 2,300 institutional and high-net-worth clients. A SOC 2 qualification or adverse finding would need to be disclosed. In an industry built on trust, that disclosure could trigger client departures. The Chief Compliance Officer estimated potential AUM loss at $500 million to $1.2 billion if the audit went badly.
Beyond the audit, the trading floor could not tolerate disruption. Traders processed an average of $85 million in daily transaction volume. Every minute of email downtime, every missed Bloomberg alert, every broken workflow represented real financial exposure. The operations team calculated that a single day of platform disruption could cost the firm $3.2 million in trading losses and operational penalties.
What Failure Looked Like
The Solution: Compliance-First Migration
EPC Group approached this engagement differently from a standard migration. Instead of starting with the technology, we started with the audit. Our first deliverable was not a migration plan — it was a SOC 2 Control Continuity Map that documented how every control currently satisfied by Google Workspace would be maintained during migration and fulfilled by Microsoft 365 post-migration.
Proprietary Migration Tool with Metadata Preservation
EPC Group's proprietary migration tool was purpose-built for Google-to-M365 migrations. Unlike off-the-shelf tools that treat Google Drive as a simple file store, our tool understands Google's native formats, permission model, and sharing architecture. Google Docs are converted to Word with formatting preservation. Google Sheets with Apps Script are flagged for manual automation rebuild. Shared Drive permissions are mapped to SharePoint site permissions with role-level accuracy.
For this engagement, the tool migrated 45 TB of data at an average throughput of 75 GB per hour. Every file transferred was checksum-validated. Every permission mapping was logged. Every Google-native file conversion was verified for formatting accuracy by automated comparison scripts.
Identity Migration: The Invisible Foundation
Moving 8,500 identities from Google to Microsoft Entra ID was the most technically delicate phase. Each user needed a new identity in Entra ID, MFA re-enrollment, Conditional Access policy assignment, and application access reconfiguration — all without being locked out of their accounts during the transition.
EPC Group deployed a coexistence period where both Google and Microsoft identities were active simultaneously. Users authenticated through a federated trust, so they experienced a single sign-on regardless of which platform their data currently resided on. The identity cutover happened transparently — users did not change passwords or re-enroll in MFA.
Custom Automation Rebuilds
The 23 custom Google Apps Script automations were rebuilt as Power Automate flows, Azure Functions, or Power Apps solutions. The compliance team's regulatory submission workflow — their most critical automation — was rebuilt in Power Apps with enhanced audit trail capabilities that actually exceeded the original Google implementation. The trading floor's notification system was migrated to Power Automate with Microsoft Teams integration, reducing alert delivery time from 30 seconds to under 5 seconds.
Compliance-First Approach
SOC 2 Control Continuity Map delivered before migration began
Metadata Preservation
45 TB migrated with full permissions, version history, and file metadata intact
Seamless Identity Migration
Federated trust enabled transparent cutover with zero account lockouts
Migration Timeline: 14 Weeks from Kickoff to Audit-Ready
Discovery & SOC 2 Mapping
Inventoried 8,500 users, 45 TB of Google Drive data, 23 custom Apps Script automations, 47 third-party integrations. Mapped SOC 2 controls to target Microsoft 365 environment. Identified regulatory audit timeline: 90 days from project start.
Identity & Security Architecture
Designed Entra ID structure. Migrated identities from Google to Microsoft with MFA enrollment. Configured Conditional Access policies. Deployed Microsoft Purview sensitivity labels for financial data classification.
Pilot Migration
Migrated 400 users across trading, compliance, and operations teams. Validated Gmail-to-Outlook experience, Drive-to-OneDrive file integrity, and calendar accuracy. Tested all 23 custom automation replacements. SOC 2 control verification in target environment.
Batch Migration
Migrated ~1,700 users per week across 5 waves. Trading floor migrated over a holiday weekend. Compliance team migrated with enhanced audit logging. Each wave included post-migration validation and user acceptance testing.
DNS Cutover & Copilot Deployment
DNS MX records switched from Google to Microsoft. All Google services deactivated. Copilot for Microsoft 365 deployed to 2,000 power users with governance guardrails. Self-service training portal launched.
Hypercare & Audit Prep
24/7 support team for first 2 weeks. SOC 2 Migration Compliance Report delivered. Regulatory audit preparation documentation compiled. Auditors cleared the platform change with zero findings.
The Results: Audit Passed. Productivity Transformed.
The SOC 2 auditors arrived on schedule. They reviewed the migration documentation, examined the control continuity evidence, and tested the Microsoft 365 environment. The finding: zero exceptions related to the platform migration.
“We bet the company on this migration. Not just because we needed Microsoft 365, but because we needed Copilot to stay competitive. EPC Group made a bet that should have taken 6 months and compressed it into 12 weeks — without a single SOC 2 finding, without a single lost file, and without a single angry trader. Our auditors said the migration documentation was the cleanest they had ever seen for a platform change of this magnitude.”
— Chief Technology Officer, Mid-Market Financial Services Firm
The Copilot Effect: Why They Migrated in the First Place
The migration was not the end goal — it was the enabler. Within two weeks of completing the migration, EPC Group deployed Copilot for Microsoft 365 to 2,000 power users: analysts, portfolio managers, compliance officers, and client relationship managers. The results were measured rigorously by the firm's operations team.
Before: 4.5 hours average
After: 45 minutes with Copilot
83% time reduction
Before: Manual notes, 30 min/meeting
After: Auto-generated, 2 min review
93% time reduction
Before: 28 minutes average
After: 11 minutes with Copilot drafts
61% faster response
Before: 3 hours from research to deck
After: 45 minutes with Copilot
75% time reduction
The overall productivity improvement measured across the 2,000 Copilot users was 40% in the first 90 days. The firm calculated this represented $3.8 million in annualized productivity value. Combined with $1.2 million in license cost savings from consolidating Google and Microsoft subscriptions, the total first-year ROI was $5 million — a 12x return on the migration investment.
Frequently Asked Questions
How long does a Google Workspace to Microsoft 365 migration take for a financial services firm?
For an organization with 8,500 users, a Google-to-M365 migration typically takes 10-14 weeks. This includes 2-3 weeks of discovery and planning, 1-2 weeks of pilot migration with 200-500 users, 6-8 weeks of batch migration, and 1-2 weeks of cutover and hypercare. Financial services firms require additional time for SOC 2 compliance validation, regulatory documentation, and security control verification. EPC Group completed this engagement in 12 weeks, including all compliance deliverables. Timeline accelerators include our proprietary migration tool which processes Gmail, Google Drive, and Google Calendar data 40-60% faster than standard tools.
How do you maintain SOC 2 compliance during a Google to Microsoft 365 migration?
SOC 2 compliance during migration requires continuous control coverage. EPC Group maintains compliance by: (1) documenting all migration processes against SOC 2 Trust Service Criteria (security, availability, processing integrity, confidentiality, privacy), (2) ensuring data encryption in transit (TLS 1.2+) and at rest (AES-256) throughout the migration, (3) implementing access controls that limit migration engineer access using just-in-time privileged access, (4) generating audit logs for every data movement operation, (5) performing control testing in the target Microsoft 365 environment before migrating regulated data, and (6) delivering a SOC 2 Migration Compliance Report that auditors can reference. In this case, the client passed their SOC 2 Type II audit 60 days after migration completion with zero findings related to the platform change.
What happens to Google Drive data when migrating to Microsoft 365?
Google Drive data migrates to OneDrive for Business (personal files) and SharePoint Online (shared drives and team files). EPC Group preserves: file and folder structure, sharing permissions (mapped from Google groups to Microsoft Entra ID groups), version history, comments and annotations, file metadata (created date, modified date, author), and Google-native file formats (Docs, Sheets, Slides are converted to Word, Excel, PowerPoint with formatting preserved). For this financial services client, we migrated 45 TB of Google Drive data with 100% fidelity. Custom Google Apps Script automations were rebuilt as Power Automate flows or Power Apps solutions.
Can you migrate custom Google Apps and integrations to Microsoft 365?
Yes. Most financial services firms have custom Google Apps Script automations, Google Forms workflows, and third-party integrations built on Google APIs. EPC Group catalogs every custom integration during discovery and creates a migration plan for each: Google Apps Script automations are rebuilt as Power Automate flows or Azure Functions. Google Forms are recreated as Microsoft Forms or Power Apps. Google Sites become SharePoint sites. Third-party integrations using Google OAuth are reconfigured for Microsoft Entra ID authentication. Google Vault archives are migrated to Microsoft Purview. In this case study, we migrated 23 custom Google Apps Script automations and 47 third-party integrations with zero functionality gaps.
What is the cost of migrating 8,500 users from Google to Microsoft 365?
An enterprise Google-to-M365 migration for 8,500 users in a regulated financial services environment typically ranges from $200,000 to $450,000 depending on data volume, custom integrations, compliance requirements, and timeline urgency. Per-user costs range from $25 to $55. This engagement included: full workload migration (Gmail, Drive, Calendar, Contacts, Sites), identity migration from Google to Entra ID, 23 custom automation rebuilds, SOC 2 compliance documentation, Copilot deployment for 2,000 power users, and 4 weeks of hypercare support. The client realized $1.2M in annual savings from license optimization and $3.8M in productivity gains from Copilot adoption within 12 months.
How does Copilot for Microsoft 365 benefit financial services firms after migration?
After migrating from Google Workspace to Microsoft 365, financial services firms gain access to Copilot for Microsoft 365, which provides AI-powered assistance across Word, Excel, PowerPoint, Outlook, and Teams. In this case study, the client deployed Copilot to 2,000 power users (analysts, portfolio managers, compliance officers) and measured a 40% productivity improvement in the first 90 days. Specific use cases: automated client report generation from Excel data, meeting summary creation for compliance documentation, email draft assistance for client communications, and PowerPoint deck creation from research notes. Copilot was deployed with data governance guardrails to prevent exposure of restricted financial data, using Microsoft Purview sensitivity labels and Conditional Access policies configured by EPC Group.
Ready to Move from Google to Microsoft 365?
EPC Group has completed 625+ Google-to-M365 migrations — more than any other Microsoft partner. Whether you are in financial services, healthcare, or any regulated industry, we deliver zero data loss and continuous compliance.