EY vs Thoughtworks: full comparison for 2026
Quick verdict
EY (4.2/5) edges ahead of Thoughtworks (3.8/5) overall. EY is the better choice for enterprises building AI risk into existing controls. Thoughtworks is the stronger option for CTOs judging build-or-buy on AI tooling. The right choice depends on how independent you need the advice to be, your regulatory exposure, and your budget.
EY vs Thoughtworks: head-to-head summary
| Criterion | EY | Thoughtworks |
|---|---|---|
| Founded | 1989 | 1993 |
| HQ | London, UK | Chicago, USA |
| Team size | ~400,000 | ~10,000 |
| Rating | 4.2 / 5 | 3.8 / 5 |
| Primary differentiator | AI risk work folded into existing technology risk and controls programs | Public Technology Radar and engineering-led build-or-buy advice |
| Pricing model | Engagement fees per scope; rates not published | Time & materials; rates not published |
| Min. engagement | Not disclosed | Not disclosed |
| Primary tech stack | EU AI Act, NIST AI RMF, GDPR | AWS, Azure, Google Cloud |
| Industries served | Financial services, Insurance, Public sector, Energy, Consumer | Financial services, Retail, Healthcare, Public sector |
EY vs Thoughtworks: overview
EY
EY was formed by the 1989 merger of Ernst & Whinney and Arthur Young and employs about 400,000 people. Its advisory teams cover responsible AI, AI risk, and compliance programs, and its technology risk leaders have spoken publicly about how far real AI assurance still has to go. That candor is useful for buyers who want an honest view of what can be certified today. Like the rest of the Big Four, it sells implementation as well.
Thoughtworks
Thoughtworks has around 10,000 people and has been based in Chicago since 1993. Apax took it private in a deal announced in August 2024, and a 2026 joint venture with New York advisory firm Teneo aims to strengthen its business advice. Its own advice is strongest on software and data foundations, and its public Technology Radar shows how it judges tools before you hire it.
Services and capabilities: EY vs Thoughtworks
| Capability | EY | Thoughtworks |
|---|---|---|
| Readiness assessment | ✓ | ✗ |
| Use-case prioritization | ✗ | ✗ |
| TCO / ROI modeling | ✗ | ✗ |
| AI governance & EU AI Act | ✓ | ✗ |
| Build vs. buy advice | ✗ | ✓ |
| Independent audit or assurance | ✓ | ✗ |
| Roadmap any vendor can implement | ✗ | ✗ |
| Delivery capability after advice | ✓ | ✓ |
Frameworks and platforms: EY vs Thoughtworks
| Framework / platform | EY | Thoughtworks |
|---|---|---|
| EU AI Act | ✓ | N/A |
| GDPR | ✓ | N/A |
| DORA | N/A | N/A |
| NIST AI RMF | ✓ | N/A |
| ISO/IEC 42001 | N/A | N/A |
| Azure | ✓ | ✓ |
| AWS | N/A | ✓ |
| Google Cloud | N/A | ✓ |
Pricing comparison: EY vs Thoughtworks
| Criterion | EY | Thoughtworks |
|---|---|---|
| Minimum engagement | Not disclosed | Not disclosed |
| Engagement models | Fixed-scope assessment, Multi-use-case advisory, Audit or certification, Delivery team | Multi-use-case advisory, Delivery team |
| Rate transparency | Not public | Not public |
| Price tier | Mid-market | Mid-market |
Target audience comparison: EY vs Thoughtworks
| Dimension | EY | Thoughtworks |
|---|---|---|
| Best company size | Enterprise | Enterprise |
| Best industries | Financial services, Insurance, Public sector | Financial services, Retail, Healthcare |
| Best use cases | Adding AI risk to an existing controls framework., Responsible AI policies for a large insurer. | Build-or-buy decisions on AI developer tools., Data foundations before AI. |
| Typical project type | Fixed-scope assessment | Multi-use-case advisory |
EY vs Thoughtworks: pros and cons
| EY | |
|---|---|
| + | Ties AI risk to controls frameworks finance teams already use |
| + | Realistic public view on the limits of AI assurance |
| + | Large global bench |
| - | Premium fees |
| - | Sells delivery alongside advice |
| - | Audit-client independence rules apply |
| Thoughtworks | |
|---|---|
| + | Tool opinions are public in its Technology Radar |
| + | Strong engineering judgment on build-or-buy |
| + | Data foundations expertise |
| - | Taken private by Apax in 2024 |
| - | Thin on regulation and governance |
| - | Advice leads naturally into delivery |
Who should choose EY?
A typical fit: adding AI risk to an existing controls framework.
AI risk work folded into existing technology risk and controls programs. Minimum engagement is not publicly disclosed. Works best with clients in Financial services, Insurance, Public sector, Energy, Consumer.
Who should choose Thoughtworks?
A typical fit: build-or-buy decisions on AI developer tools.
Public Technology Radar and engineering-led build-or-buy advice. Minimum engagement is not publicly disclosed. Works best with clients in Financial services, Retail, Healthcare, Public sector.
Decision matrix: EY vs Thoughtworks
| Your situation | Recommended choice |
|---|---|
| You want advice with no build contract attached | Neither; write the build as a separate decision |
| Finance needs run costs before approving anything | Neither lists cost modeling; ask for a sample |
| Some of your use cases may be high-risk under the EU AI Act | EY |
| You need an outside check on a system already built | EY |
| You want the same firm to build what it recommends | Both can deliver |
| Your budget is at the lower end | Compare: EY (Not disclosed) vs Thoughtworks (Not disclosed) |
| You need advisers in many countries at once | EY |
Use case fit: EY vs Thoughtworks
| Use case | EY fit | Thoughtworks fit | Winner |
|---|---|---|---|
| Adding AI risk to an existing controls framework. | Strong | Limited | EY |
| Responsible AI policies for a large insurer. | Strong | Limited | EY |
| Build-or-buy decisions on AI developer tools. | Limited | Strong | Thoughtworks |
| Data foundations before AI. | Limited | Strong | Thoughtworks |
Verdict: EY vs Thoughtworks
EY (4.2/5) is the stronger overall choice for most AI Advisory projects. AI risk work folded into existing technology risk and controls programs.
Thoughtworks (3.8/5) is worth a look if you need data foundations before AI. If your situation matches that, Thoughtworks is a competitive option.
Related comparisons
EY vs Thoughtworks FAQ
Is EY better than Thoughtworks?
EY (4.2/5) scores higher overall, but "better" depends on your use case. EY's strongest advantage: ties AI risk to controls frameworks finance teams already use. Thoughtworks's strongest advantage: tool opinions are public in its Technology Radar.
How do EY and Thoughtworks differ in pricing?
EY's pricing: engagement fees per scope; rates not published. Thoughtworks's pricing: time & materials; rates not published. Any hourly bands shown come from Clutch, not a published rate card, so a scoping call is still needed for a project quote.
Which is better for enterprise: EY or Thoughtworks?
EY is the larger team and typically the better enterprise-scale choice. For very large programmes, verify team size and compliance coverage directly with each firm before shortlisting.
What are the main differences between EY and Thoughtworks?
EY's primary differentiator is: AI risk work folded into existing technology risk and controls programs. Thoughtworks's primary differentiator is: public Technology Radar and engineering-led build-or-buy advice. They also differ in team size (~400,000 vs ~10,000), minimum engagement (Not disclosed vs Not disclosed), and primary industries served (Financial services, Insurance vs Financial services, Retail).
Verify all details directly with each firm before making a decision.