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EY UK • Madrid Torre Azca

Six Sigma Black Belt - Tax Process Reinvention

Employment type:  Full time
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Job Description

At EY, we’re all in to shape your future with confidence.

We’ll help you succeed in a globally connected powerhouse of diverse teams and take your career wherever you want it to go.

Join EY and help to build a better working world.

The opportunity

EY’s Global Tax Centre of Excellence Data & AI team play a prominent role in leading client transformation initiatives that leverage Data & AI as core capabilities. The CoE seeks to architect reusable patterns and process blueprints to bootstrap scalability across all the EY Tax technology teams in all key markets.

You will have an existing opportunity to stay on the leading edge of technology development and to contribute to the successful transformation of EY tax and its clients.

Role Purpose

The Six Sigma Black Belt is a foundational role within the Tax Process Reinvention & Agentic AI CoE.

The role is responsible for deep task‑level decomposition of tax processes and data flows, identification and quantification of waste, and the design of Lean‑optimised To‑Be processes that are explicitly engineered to support agentic AI workflows.

This role ensures that AI is applied to the right work, in the right way, at the right time — and is not layered on top of broken or inefficient processes.

Key Responsibilities

Process Decomposition & Lean Analysis

  • Lead Lean Six Sigma DMAIC reviews across Tax service lines (CIT, PAS, Indirect Tax, Transfer Pricing, WHT)
  • Decompose end‑to‑end tax processes to atomic task level, explicitly defining:
    • inputs and outputs
    • decision points
    • hand‑offs
    • exception paths
    • Produce Value Stream Maps (As‑Is and To‑Be) with quantified metrics (cycle time, lead time, takt time, capacity utilisation)

Waste Identification & Quantification

  • Apply the 8 Wastes framework systematically to identify:
    • non‑value‑added activity
    • bottlenecks and delays
    • duplication and rework
  • Quantify improvement opportunities to support:
    • business cases
    • prioritisation of agent candidates
    • phased transformation roadmaps

AI‑Ready Process Design

  • Partner closely with the Data & AI Architect to:
    • identify tasks suitable for agent execution
    • define Human‑in‑the‑Loop control points
    • shape agent‑to‑agent and workflow‑to‑agent interactions
  • Ensure future‑state processes are:
    • standardised
    • auditable
    • scalable across jurisdictions and clients

CoE & Capability Development

  • Act as process authority within the Tax Process Reinvention & Agentic AI CoE
  • Develop reusable Lean artefacts and patterns for repeat client delivery
  • Coach client and EY teams on Lean‑led AI enablement

Required Experience & Background

  • Certified Six Sigma Black Belt (or equivalent practical experience)
  • Proven delivery of Lean transformations in complex, regulated environments
  • Strong experience decomposing knowledge‑heavy processes (tax, finance, compliance, or adjacent domains)
  • Comfortable working alongside technologists, data engineers, and AI specialists
  • Experience presenting quantified improvement cases to senior stakeholders
  • Strong interpersonal, workshop facilitation skills

Desirable Experience

  • Prior work in Tax, Finance, or Professional Services
  • Exposure to workflow platforms (e.g. ServiceNow) or platform‑based operating models
  • Experience supporting automation or AI initiatives (even if not hands‑on)

Success Measures

  • Quality and clarity of task‑level process decomposition
  • Reduction in non‑value‑added work prior to automation
  • Smooth hand‑off from Lean design to agent build
  • Reuse of Lean artefacts across engagements

What we offer you

At EY, we’ll develop you with future-focused skills and equip you with world-class experiences. We’ll empower you in a flexible environment, and fuel you and your extraordinary talents in a diverse and inclusive culture of globally connected teams. Learn more.

Are you ready to shape your future with confidence? Apply today.

To help create an equitable and inclusive experience during the recruitment process, please inform us as soon as possible about any disability-related adjustments or accommodations you may need.

EY | Building a better working world

EY is building a better working world by creating new value for clients, people, society and the planet, while building trust in capital markets.

Enabled by data, AI and advanced technology, EY teams help clients shape the future with confidence and develop answers for the most pressing issues of today and tomorrow.

EY teams work across a full spectrum of services in assurance, consulting, tax, strategy and transactions. Fueled by sector insights, a globally connected, multi-disciplinary network and diverse ecosystem partners, EY teams can provide services in more than 150 countries and territories.

Apply now

Company benefits

27 days annual leave + bank holidays
Adoption leave
Annual bonus
Buddy scheme
Buy or sell annual leave
Car allowance
Career and family coaching
Charity donation scheme
Coaching
Critical Illness Insurance
Cycle to work scheme
Dental coverage
Discretionary sick pay
Electric Car Salary Sacrifice
Employee discounts
Employee recognition scheme
Enhanced maternity leave
Enhanced paternity leave
Enhanced pension match/contribution
Eye Care Support – (free eyesight testing)
Financial advice
Health assessment
Health insurance
In house training
Income protection
Joining bonus
L&D budget
Learning platform
Life assurance
Lunch and learns
Menopause support
Mental health pathway
Mentoring
Personal development days
Physiotherapy
Professional subscriptions
Referral bonus
Shared parental leave
Special leave
Sports teams
Study support
Studying sabbaticals
Surrogacy leave
Wellbeing allowance – £500
Wellbeing incentive programme
Carer’s leave – Special Leave (4 weeks paid)

Working at EY UK

Company employees:

400000

Gender diversity (m:f):

52:48

Hiring in countries

Australia

Canada

France

Guernsey

Italy

Jersey

Netherlands

Spain

Sweden

Switzerland

United Kingdom

United States

Office Locations

Awards & Accreditations

2nd - Most Inclusive Company

2nd - Most Inclusive Company

Flexa awards 2026
Best Career Progression

Top 10 - Best Career Progression

Flexa awards 2026

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