Top 5 IT consulting firms in the US, and how to choose one

There is no official ranking of IT consulting firms, but five names appear on many US shortlists for large technology programmes: Accenture, Deloitte, IBM Consulting, McKinsey & Company and PwC. They differ in hands-on delivery, pricing and typical clients, so pick by the work you need: strategy, implementation or ongoing infrastructure operations.

Key takeaways

• Accenture and Deloitte are the two largest by published revenue: US$69.7 billion (Accenture, fiscal 2025) and US$70.5 billion (Deloitte, global, fiscal 2025).
• IBM Consulting is one segment of IBM. Its managed infrastructure services business was separated into Kyndryl in November 2021.
• McKinsey is a strategy firm first; it does technology work, but it does not publish revenue the way listed companies do.
• Published "best firm" lists mix peer votes, client reviews and analyst scoring. Read the method before you trust the order.
• For cloud and IT infrastructure work, a certified mid-size partner is often a better fit than a global consultancy, especially below enterprise scale.

What counts as an IT consulting firm?

A firm in this category advises on, designs and often delivers technology changes: cloud migration, ERP and CRM programmes, data platforms, security and, increasingly, AI. The large firms bundle several types of work that buyers should keep apart.

• Strategy and advisory: technology strategy, operating model, business cases, due diligence.
• Systems integration: implementing platforms such as SAP, Salesforce, ServiceNow or a cloud landing zone.
• Managed services: running applications or infrastructure after go-live, under a service level agreement.
• Infrastructure consulting: network, data centre, cloud architecture and operations design.

Most of the search traffic to this page asks about IT infrastructure consulting specifically. That is the area where the big names are least differentiated and where specialist partners compete hardest, so we cover it separately below.

The five firms most often shortlisted

The order below is alphabetical, not a ranking. Revenue figures are taken from each company's own results releases and are global unless stated; none of these firms reports a clean US-only technology consulting number.

Accenture

Accenture is a listed professional services company focused on technology. For the fiscal year ended 31 August 2025 it reported revenue of US$69.7 billion and generative AI new bookings of US$5.9 billion, with approximately 779,000 people serving clients in more than 120 countries, according to its fiscal 2025 results release. Its strength is scale in systems integration and outsourcing. The trade-off is that you are one of many large accounts, and delivery quality depends heavily on the team you get.

Deloitte

Deloitte is the largest of the Big Four professional services networks by reported revenue. It reported aggregate global revenue of US$70.5 billion for the fiscal year ending 31 May 2025 and a workforce of over 470,000, per its FY2025 revenue announcement. That figure covers audit, tax and legal as well as consulting. Technology work sits mainly in its Technology & Transformation business, alongside Strategy, Risk & Transactions. One practical point: if Deloitte audits your company, independence rules limit which consulting services it can sell you.

IBM Consulting

IBM Consulting is the services arm of IBM. In the fourth quarter of 2025 it reported consulting revenue of US$5.3 billion, and full-year consulting revenue grew 2 percent (flat at constant currency), according to IBM's fourth-quarter 2025 results. It is strong where IBM software, hybrid cloud and mainframe estates are involved. Note that IBM moved classic infrastructure outsourcing out of the company: it completed the separation of its managed infrastructure services business to Kyndryl on 3 November 2021.

McKinsey & Company

McKinsey is one of the three "MBB" strategy firms, with Boston Consulting Group and Bain & Company. It is privately owned by its partners and does not publish annual revenue in the way listed companies or the Big Four networks do. McKinsey is usually hired for technology strategy, digital and AI operating models, and large cost or transformation programmes at board level. It does less long-running implementation than Accenture or Deloitte, so many clients pair it with an integrator.

PwC

PwC is another Big Four network. It is organised around assurance, tax and advisory, and its technology consulting sits inside advisory. Like Deloitte, it combines technology work with risk, controls and finance expertise, which suits regulated industries and finance-led programmes such as ERP replacements. The same audit-independence limits apply if PwC is your auditor.

How the five compare

How are consulting firm rankings put together?

Most published rankings use one of three methods, and each favours a different kind of firm.

• Peer votes: consultants rate competitors' prestige. This tends to favour strategy firms.
• Client and peer surveys plus capability scoring: lists such as Consultancy.us rankings combine reviews with an assessment of each firm's track record by service area.
• Analyst evaluations: research firms score vendors in a defined market, usually behind a paywall.

None of these tells you how a firm will perform on your project. Use them to build a long list, then judge firms on the team, references and contract terms.

Who are the best IT infrastructure consulting providers?

For infrastructure work the honest answer is "it depends on your platform". The global firms can design an infrastructure strategy, but much of the hands-on cloud and operations work is done by specialist partners, often subcontracted.

What to look for in an infrastructure partner:

• Verified cloud credentials: partner tier and competencies with AWS, Microsoft Azure or Google Cloud, which you can check in each provider's partner directory.
• Engineers, not only advisers: ask who writes the infrastructure as code and who carries the pager after go-live.
• Run as well as build: a partner that also offers managed services has a reason to design something it can operate.
• Cost discipline: FinOps practices and clear reporting on cloud spend, not just a migration plan.
• Security and compliance: experience with the rules you face, such as NIS2 in the EU or sector rules in the US.

How to choose an IT consulting partner

1. Define the outcome first. "Move 60 workloads to AWS by Q3 with a cost target" gets better proposals than "help with cloud".
2. Match the firm to the work. Strategy firms for board-level decisions, integrators for big platform programmes, and specialist IT consultancies for cloud and infrastructure.
3. Meet the delivery team. Ask for named people and how much of their time you get.
4. Check two references of similar size. A Fortune 100 reference says little about how the firm treats a mid-size client.
5. Agree what happens after go-live. Hand-over, documentation and support terms belong in the contract.
6. Compare pricing models. Fixed price for well-defined scope, time and materials for discovery, and outcome-based terms only when you can measure the outcome.

How Opsio helps

Opsio, the publisher of this article, is not one of the five firms above. We are a cloud consultancy and managed service provider with offices in Karlstad, Sweden and Bangalore, India, and an AWS Advanced Tier Services Partner. We work on cloud strategy, AWS migration and the operations that follow.

For example, Opsio moved Swedish ski resort group Branäsgruppen from a VMware estate to AWS. The Branäsgruppen case reports 40% faster average page responsiveness, a 40% reduction in total cost of ownership and 99.9%+ application uptime. For a wider view of the market, see our overview of the Big 4 consulting firms.

Frequently asked questions

What is the largest IT consulting firm in the US?

By published global revenue, Accenture (US$69.7 billion for fiscal 2025) and Deloitte (US$70.5 billion for fiscal 2025) are the two largest. Deloitte's figure includes audit and tax, and neither firm reports a US-only figure for this work, so a precise US ranking is not possible from public data.

What is the difference between MBB and the Big Four?

MBB (McKinsey, BCG, Bain) are strategy firms that mostly advise. The Big Four (Deloitte, PwC, EY, KPMG) are audit-led networks that also sell large technology implementation and managed services. Many large programmes use one of each.

Are smaller consultancies better for mid-size companies?

Often, yes. A mid-size client is a priority account for a specialist, gets senior people more easily and usually pays lower day rates. The trade-off is less breadth across industries and countries.

How do I check an IT consultancy's cloud credentials?

Look the firm up in the partner directory of AWS, Microsoft or Google Cloud. Directories show partner tier, validated competencies and published customer references, which are harder to inflate than a marketing page.

Should one firm do both strategy and implementation?

It reduces hand-over friction, but it also removes an independent check on the plan. A common compromise is to buy strategy and implementation separately, or to have a small independent reviewer on large programmes.

For hands-on delivery in India, see it consulting.

Related reading: Top IT Firms in India.

Related reading: Top Audit Firms in Bangalore.