Global Tax Management
Corporate tax services firm supporting mid-sized and large companies with tax accounting, compliance, automation and co-sourced tax operations.
gtmtax.comGlobal Tax Management, commonly branded GTM Tax, was founded in 1995 to support corporate tax departments. It works with companies that need specialist capacity, recurring operating support or modernization of tax processes.
Services include tax accounting and provision, income-tax compliance, international tax, state and local tax, indirect tax, transfer pricing, credits and incentives, automation, outsourcing and co-sourcing. GTM also participates in the WTS Global network.
Principal activities
Tax planning, structuring, compliance coordination and support for corporate tax departments.
Cross-border planning, transaction support, transfer pricing and ownership-structure analysis.
Tax accounting, provision support, credits, incentives, indirect tax and technology-enabled processes.
- Typical clients: Corporations, private businesses, investment firms, in-house tax departments, finance leaders and professional advisers.
- Engagement context: Corporate tax planning, cross-border operations, transactions, reporting, indirect tax, credits, incentives and tax-process improvement.
Global Tax Management operates where tax rules interact with corporate structure, capital allocation, transactions, reporting obligations and operating processes. View the firm’s relevant services ↗
Sector and mandate coverage
- Corporate and private businesses
- Technology
- Manufacturing
- Financial services
- Real estate
- Consumer markets
- Corporate tax planning
- International tax
- Transaction tax
- Tax accounting and provision
- State and local tax
- Credits and incentives
The precise scope depends on the taxpayer, jurisdictions, legal entities, ownership structure, transaction perimeter and reporting requirements. Tax advice may require coordination with legal counsel, auditors, valuation specialists, technology providers and local professional firms.
Market position
Global Tax Management is positioned as a corporate tax services and technology firm. Its relevance reflects the depth of its tax specialization, corporate-client orientation, technical delivery model and ability to support complex or recurring tax requirements.
Distinctive focus: Direct alignment with the recurring technical, staffing and technology needs of in-house corporate tax functions.
Competitive context
Global Tax Management competes with tax-led professional-services firms, independent accounting networks, specialist consultancies and tax-technology platforms. The relevant peer set varies by jurisdiction, client size, tax type and whether the mandate requires strategic advice, compliance execution, specialist documentation or software.
Comparable firms are selected according to overlap in business model, client segment, service coverage, geographic activity and mandate profile. Inclusion does not imply an exhaustive competitor set or an equivalence in scale, ranking or market position.
Leadership
| Person | Current position | Institutional background |
|---|---|---|
| David Sekula | Chief Executive Officer and Executive Director | Corporate tax services and firm leadership |
| John Diamond | Managing Director and Chief Operations Officer | Operations and New York metropolitan leadership |
| Ryan Lynch | Managing Director and Chief Growth Officer | Growth strategy and client development |
Leadership information reflects the roles available in the public sources reviewed on 20 August 2026. View current leadership information ↗
Corporate and regulatory information
Global Tax Management provides tax, accounting, advisory or tax-technology services. The precise professional and regulatory framework depends on the contracting entity, jurisdiction and engagement scope.
View registered-entity details
| Principal entity | Global Tax Management, Inc. |
| Professional status | Service- and jurisdiction-specific |
| Registration identifier | N/A |
| Headquarters | Wayne, Pennsylvania |
| Primary jurisdiction | United States |
Principal offices
- Wayne
- New York City
- Pittsburgh
- Cincinnati
- Washington, D.C.
Rankings and recognition
Ranking inclusion is editorially determined. The existence or maintenance of a Wiki profile does not influence ranking eligibility, tier or position.
Related institutions and subjects
Sources and data transparency
The following sources were accessed on 20 August 2026:
- Corporate Tax Services — corporate tax, specialty tax or tax-technology capabilities.
- Global Tax Management — firm overview, services and institutional information.
- Advisory Ranking — Top 20 Corporate Tax Advisory 2026 inclusion and tier classification.
