Deloitte Client List: Who Does Deloitte Actually Work With?

From Microsoft to Morgan Stanley: Inside Deloitte's Client Roster — And How KPMG, EY, and PwC Compare

Deloitte audits nearly 90% of the Fortune 500. That's not a marketing line — it's backed by publicly filed data. With 926 SEC registrant audit clients and $70.5 billion in global revenue in FY2025, Deloitte is the largest professional services firm in the world. But knowing who they actually work with — and how that compares to KPMG, EY, and PwC — is the kind of detail that sharpens your application strategy and tells you where the real work happens.

Whether you're targeting audit, consulting, tax, or advisory, understanding Deloitte's client mix tells you a lot about where the real demand is — and which skills to prioritise.

The Scale of Deloitte's Reach — And Where the Other Three Sit

The Big 4 collectively audit 100% of the Fortune 500. But market share within that group is not equal.

1. Deloitte — 926 SEC registrant clients, 15% market share. Largest client base in the Big 4. Strongest in digital transformation, tech, and government services. Revenue hit $70.5B in FY2025.
2. EY — 799 SEC clients, 13% market share. Known for private equity advisory through EY-Parthenon. Expanding aggressively into strategy consulting.
3. PwC — 744 SEC clients, 12% market share. Strong in financial services, TMT (tech, media, telecom), and global tax advisory.
4. KPMG — 639 SEC clients, 11% market share. Specialist in regulated industries; financial services and private equity due diligence are core strengths.

Deloitte's lead isn't marginal — and it shows in the calibre and range of clients they attract.

Deloitte's Biggest Individual Clients

Deloitte's top clients read like a who's who of global business. Some of the biggest names on their books include:

• Microsoft — one of Deloitte's largest and longest-standing audit clients, anchoring the firm's tech sector dominance
• Morgan Stanley — a flagship financial services relationship spanning audit and advisory
• Berkshire Hathaway — audit and advisory services for one of the world's most valuable companies
• MetLife — Deloitte's largest insurance audit client
• Boeing — paid Deloitte $34.8 million in audit fees in 2023 alone
• Procter & Gamble — consumer goods giant with deep advisory ties
• Apollo Global Management and Blackstone Group — two of the world's largest private equity firms
• General Motors — major automotive sector relationship

These aren't just logos on a slide. These are relationships that run deep — audit, tax, advisory, and transformation projects running in parallel across years, sometimes decades.

Industries Where Deloitte Dominates

Deloitte's client base spans more than 20 industries, but a handful of sectors drive the bulk of revenue and headcount.

• Financial Services — Deloitte's single largest sector, generating around $18 billion in FY2024 — roughly 25% of total firm revenue. Banking, capital markets, insurance, and investment management all sit here. Deloitte audits 28% of companies in the S&P 500 Financials sector.
• Technology, Media & Telecom (TMT) — Clients like Microsoft anchor a powerhouse digital practice covering cloud strategy, cybersecurity, and AI implementation. Deloitte audits 15% of S&P 500 companies in the Information Technology sector.
• Government & Public Services — Deloitte pulls in more federal contracting revenue than any other Big 4 firm: $4 billion in US federal contracts in 2024 alone. EY and KPMG each brought in under $650 million in the same period.
• Life Sciences & Healthcare — Regulatory advisory, clinical operations consulting, and digital health transformation across major pharma and hospital networks.
• Consumer & Industrial Products — Supply chain, operations, and sustainability advisory for major manufacturers and retailers.

What Deloitte's Client Mix Means for Your Career

This isn't just trivia — it's application strategy. Knowing which industries Deloitte dominates tells you where the roles are concentrated, and what profile makes you competitive.

1. Target the right service line for your background: Finance or accounting graduates should look at audit or tax. Business and economics majors fit naturally into consulting. Tech backgrounds are increasingly valuable in Deloitte's fast-growing digital and AI practices. Match your CV to the service line, not just the firm name.
2. Research your target sector before any interview: If you're applying to Deloitte's financial services practice, knowing that Berkshire Hathaway, MetLife, and Morgan Stanley are on their books shows you've done your homework — and interviewers notice.
3. Don't overlook the public sector: Deloitte's government practice is enormous and less competed-for than private sector roles. If you're drawn to policy, health agencies, or defence work, Deloitte is leagues ahead of KPMG and EY in this space.
4. Use firm-specific events to connect with the right teams: Deloitte runs industry-specific insight sessions, graduate showcases, and virtual events across each of these sectors. Showing up to a financial services-focused event when you're targeting that practice is a simple edge most applicants skip. You can find them at big4events.com/events.

Finding Events Tied to Deloitte's Key Sectors

Deloitte, KPMG, EY, and PwC all run events tied directly to their client-facing practices. The ones most relevant to landing a role in the sectors above include:

• Industry insight sessions — hosted by financial services, tech, or public sector practice teams; gives you a real feel for the work
• Graduate open days — where you meet partners from the specific service lines you're targeting
• Networking evenings — particularly useful for roles in capital markets, banking, and professional services
• Virtual webinars — Deloitte regularly runs these across audit, consulting, and government sectors; low barrier to attend, high signal to mention in applications
• Application workshops — often sector-specific; attending one focused on financial services or TMT signals genuine interest before you've even submitted your CV

Start Where the Clients Are

Deloitte doesn't work with nearly every major corporation by accident. Their client base reflects decades of relationship-building across audit, tax, and advisory — and it's still growing. Understanding that Microsoft, Boeing, and Morgan Stanley are on their books isn't just interesting context. It's a map of where the work happens, which teams are hiring, and what knowledge you need when you're in the room.

The same logic applies across KPMG, EY, and PwC: each firm's client concentration tells you something real about the culture, skills valued, and career paths available. Deloitte's tilt toward tech, government, and financial services is a signal — not just a fact.

Check the latest events across Deloitte, KPMG, EY, and PwC — browse all upcoming Big 4 events here and find your way into the sectors that interest you most.