Tanner Mainstain Glynn & Johnson

What Tanner Mainstain Glynn & Johnson does

Tanner Mainstain Glynn & Johnson (TMGJ) is a specialty business management and financial concierge firm founded in 1976 by Bill Tanner to serve the unique financial needs of Hollywood professionals. The firm provides three core service lines: CFO and Family Office Services (accounting, billpay, bookkeeping, cashflow analysis, budgeting, forecasting, HR/payroll management, financial analysis and reporting); Financial + Estate Planning (lifetime goal setting, estate and gift planning, insurance risk management, investment consultation); and Tax Services (strategic tax planning and preparation for federal, state, and local returns, plus audit representation). TMGJ has been consolidated into Ground Control Business Management (GCBM), which on April 25, 2024 became a wholly-owned subsidiary of Aon plc operating within the NFP/Wealthspire affiliate network alongside other retained brands Philpott Meeks (founded 1984) and Savitsky, Satin, Bacon & Bucci (founded 1990).

TMGJ targets high-net-worth individuals across three primary personas: entertainment industry professionals (actors, producers, writers, directors, musicians, composers, photographers, studio executives, and talent representatives); professional athletes (golfers, boxers, footballers, cricketers, MMA fighters); and outside HNW entrepreneurs and executives. The firm addresses financial complexity specifically tied to irregular income, royalty structures, image-rights taxation, multi-jurisdictional tax obligations, and career transitions — capabilities validated by Variety Business Manager Elite Awards to founders Bill Tanner (2019) and George Savitsky (2014).

The business model is relationship-based professional services delivered through retainer and hourly billing across six office locations: Los Angeles (Century City, Encino, Santa Clarita), Nashville, London, and the Midlands (UK). Client acquisition is exclusively referral-driven, sourced from existing clients, talent agents, attorneys, and entertainment industry networks; no inbound marketing or digital channels are disclosed. Under the GCBM/Aon umbrella, TMGJ gains implicit cross-sell access to adjacent insurance, benefits, retirement, and HR solutions offered by NFP subsidiaries.

Name

Tanner Mainstain Glynn & Johnson

Legal name

Ground Control Business Management

Website

https://tmgjbm.com

Company type

Private

Founded year

1976

Operating status

Operating

Headcount range

11–50 employees

Short description

Tanner Mainstain Glynn & Johnson is a specialty business management and financial concierge firm, founded in 1976, serving high-net-worth entertainment industry professionals, professional athletes, and entrepreneurs with CFO, estate planning, and tax services. It now operates as a retained brand under Aon plc subsidiary Ground Control Business Management.

Ownership category

akta.pro rank

Product category

Business Management Services

NAICS

Accounting, Tax Preparation, Bookkeeping, and Payroll Services (5412), Portfolio Management and Investment Advice (523940)

SIC

Services-Engineering, Accounting, Research, Management (8700), Investment Advice (6282)

akta.pro primary industry

Private Banking & UHNW Wealth Advisory (FSAEABAC)

Keywords

• Business management services
• Entertainment tax planning
• Financial concierge services
• Estate planning services
• Athlete financial management

Headquarters

HQ city

Los Angeles

HQ country

United States

HQ region

North America

Offices6 records

Markets served

GTM type

B2C

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Business Management Services: Comprehensive financial concierge services including accounting, billpay, bookkeeping, cashflow analysis, budgeting, forecasting, HR and payroll management, financial analysis and reporting, estate and gift planning, insurance risk management, investment consultation, and tax preparation. Revenue derived from professional service fees, likely retainer or hourly billing arrangements typical of business management firms.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels1 record

Core offering

Tanner Mainstain Glynn & Johnson is a business management firm that acts as a financial concierge for high-net-worth individuals in entertainment, sports, and business. The firm delivers accounting, billpay, bookkeeping, cashflow analysis, budgeting, forecasting, HR and payroll management, financial analysis and reporting, estate and gift planning, insurance risk management, investment consultation, and tax preparation and planning services. These services are designed to address the unique financial complexities of entertainment and athletic careers, including irregular income, international tax obligations, royalty structures, and career transitions.

Product overview

Ground Control Business Management is a financial concierge and business management firm offering a unified suite of services for high-net-worth individuals in entertainment, sports, and business sectors. The portfolio consists of three core service lines: CFO and Family Office Services (accounting, bookkeeping, cashflow management, HR/payroll), Financial + Estate Planning (wealth preservation, estate planning, investment consultation), and Tax Services (strategic tax planning, preparation, and audit representation). These services are designed to address the unique financial complexities of careers in Hollywood and professional athletics.

Differentiator

Problem solved

Functional benefit

Products and services

• CFO and Family Office Services Comprehensive financial management services including accounting, billpay, bookkeeping, cashflow analysis, budgeting, forecasting, HR and payroll management, and financial analysis and reporting for high-net-worth individuals in entertainment, sports, and business sectors.
• Financial + Estate Planning Financial and estate planning services including lifetime goal setting, estate and gift planning, insurance risk management, and investment consultation for high-net-worth individuals.
• Tax Services Strategic tax planning and preparation services covering federal, state, and local returns, including tax projections and audit representation for entertainment, sports, and high-net-worth clients.

Segments3 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Partnerships

Two partnerships are on record, tiered core.

• WealthspirecoreOthersGround Control Business Management is a Wealthspire company. Wealthspire is a platform for affiliated financial services companies.
• NFP Corp.coreOthersGCBM is part of NFP Corp. ecosystem, which includes subsidiary companies providing insurance brokerage and consulting services. NFP is now an Aon company.

Scale indicators1 record

Recent moves6 records

Expansion highlights5 records

Broad incumbents

• Bessemer Trust: Private wealth management and investment advisory firm serving ultra-high-net-worth families, including entertainment dynasties. Competes with TMGJ for HNW entertainer/athlete wealth, but emphasizes investment management and trust services over business management.
• Citrin Cooperman: National accounting and advisory firm with an Entertainment, Music, and Sports practice group providing business management, royalty accounting, and tax services. Comparable in client segment, but at significantly larger firm scale.
• BDO USA: Top-tier global accounting network with an Entertainment & Media practice serving production companies, talent agencies, and high-net-worth artists. Overlaps with TMGJ's entertainment clientele but operates as a much larger, multi-service platform.
• Marcum LLP: Large national accounting and advisory firm with a dedicated Entertainment, Sports & Media Business Management practice. Competes for the same A-list entertainment client base and offers a broader advisory portfolio and technology investments that a boutique like TMGJ cannot match.
• Crowe LLP: Top-10 U.S. accounting and advisory firm with an Entertainment and Sports practice serving performers, agents, and creatives. Comparable in client type (entertainment and athletes) and tax/accounting focus, but with a substantially broader national footprint.

Others

• Aon plc: Global professional services conglomerate (parent company of GCBM/TMGJ since April 2024) providing risk, retirement, and health solutions. Not a direct competitor but the parent and platform; provides capital, distribution, and insurance capabilities that TMGJ leverages for client solutions.

Direct peers

• Withum: Top-30 accounting and advisory firm with a dedicated Business Management & Family Office practice serving entertainment industry clients, athletes, and high-net-worth individuals. Directly comparable in client base (actors, producers, musicians) and service mix (accounting, tax, royalty advisory).
• PKF O'Connor Davies: Mid-sized accounting firm with an established Entertainment & Sports Business Management practice serving performers, athletes, and creative industry clients. Comparable to TMGJ in providing integrated accounting, tax, royalty, and tour accounting for entertainment professionals.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/tanner-mainstain-glynn-johnson

Revenue estimate

Valuation estimate

Number of profiles

Profiles16 records

Subsidiaries38 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Tanner Mainstain Glynn & Johnson