Sisterson & Co. LLP

What Sisterson & Co. LLP does

Sisterson & Co. LLP is a privately held certified public accounting and advisory firm headquartered in Pittsburgh, Pennsylvania, founded in 1926 by Douglas G. Sisterson. The firm operates from a single office in the Union Trust Building under a "one firm, one office, one mission" philosophy and is structured as a partnership of 16 individuals with an organically grown, multi-generational ownership base. It is one of the largest independently owned CPA and advisory firms in the Pittsburgh region.

The firm delivers three core practice areas — audit and assurance, tax, and advisory — with advisory further broken into collateral field examinations for secured lenders, business valuations, and quality of earnings/due diligence engagements. Services are deployed across nine industry specialty teams: manufacturing, distribution and commercial services; energy and related industries; not-for-profit; employee benefit plans; private investment companies; real estate and development; technology; individuals and trusts; and field examinations for secured lenders. Client delivery is direct, with partner involvement in every engagement, supported by AGN International membership for cross-border referral reach.

Revenue is generated almost entirely through fee-based professional services engagements, with no public pricing; ancillary income comes from a 3% credit card processing fee on online client payments. Distribution is relationship-driven via referrals, the firm website and blog, professional association participation, and community involvement, with services delivered locally, regionally, and nationally. The firm holds the highest PICPA peer review rating ("pass"), is registered with the PCAOB, and participates in multiple AICPA quality centers.

Name

Sisterson & Co. LLP

Legal name

Sisterson & Co. LLP

Website

https://sisterson.com

Company type

Private

Founded year

1926

Operating status

Operating

Headcount range

101–250 employees

Short description

Sisterson & Co. LLP is a privately held Pittsburgh-based CPA and advisory firm founded in 1926, offering audit, tax, and advisory services across nine industry specialties to clients locally, regionally, and nationally.

Ownership category

akta.pro rank

Headquarters

HQ city

Pittsburgh

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

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

Revenue model

1. Audit & Assurance Services: Audit, review, and compilation services for privately held businesses, not-for-profit organizations, employee benefit plans, and other entities. Includes agreed-upon procedures, compliance attestation, financial statement audits, forensic accounting, and internal control evaluation.
2. Tax Services: Tax compliance and sophisticated tax planning strategies for businesses, individuals and trusts. Services include business acquisitions, estate planning, international tax, R&D tax credits, state and local tax, and tax examinations representation.
3. Advisory Services: Consulting services including field examinations for secured lenders, business valuations, due diligence/quality of earnings reviews, and other tailored due diligence engagements for transactional advisory services.
4. Online Payment Processing: Provides online payment method for clients with a 3% processing fee applied to all credit card transactions.

Pricing tiers

Go-to-market motion3 records

Distribution channels2 records

Marketing channels5 records

Core offering

Sisterson & Co. LLP is an independently owned certified public accounting and advisory firm that delivers audit and assurance, tax compliance and planning, and advisory services—including collateral field examinations for lenders, business valuations, and due diligence/quality of earnings reviews—to privately held businesses, not-for-profits, employee benefit plans, financial institutions, high-net-worth individuals, and energy/technology companies. The firm operates from a single downtown Pittsburgh office, with all work delivered through partner-led engagements and industry-specialized teams covering nine vertical practices.

Product overview

Sisterson & Co. LLP is a certified public accounting and advisory firm offering a unified portfolio of professional services organized around practice areas and industry specialties. The firm's core service lines are Audit & Assurance Services, Tax Services, and Advisory Services (which encompasses Field Exams for Secured Lenders, Business Valuations, and Due Diligence/Quality of Earnings). These core offerings are delivered across nine industry specialty practices: Employee Benefit Plans, Energy & Related Industries, Individuals & Trusts, Manufacturing/Distribution/Commercial Services, Not-for-Profit, Private Investment Companies, Real Estate & Development, and Technology. The firm operates from a single office in Pittsburgh and does not offer software products; all offerings are professional services engagements.

Differentiator

Problem solved

Functional benefit

Products and services

• Audit & Assurance Services Audit, review, and compilation services for privately held businesses, not-for-profit organizations, employee benefit plans, and other entities; includes financial statement audits, agreed-upon procedures, compliance attestation, internal control evaluation, and forensic accounting.
• Tax Services Tax compliance and sophisticated tax planning strategies for businesses, individuals, and trusts, including business acquisitions, estate planning, international tax, R&D tax credits, state and local tax, and tax examination representation.
• Advisory Services Business advisory services including field examinations for secured lenders, business valuations, quality of earnings reviews, due diligence, and transactional advisory services for mergers and acquisitions.
• Field Exams for Secured Lenders Collateral field examination services for commercial lenders, including accounts receivable verification, inventory analysis, cash review, insurance coverage review, and borrowing base certificate analysis for new and existing loans.
• Business Valuations Business valuation services prepared by certified valuation analysts for mergers, acquisitions, estate planning, divorce, buy-sell agreements, shareholder disputes, and litigation purposes.
• Due Diligence & Quality of Earnings Quality of earnings reports and due diligence services for buyers, sellers, and investors in connection with business sales, acquisitions, and investments.
• Employee Benefit Plan Services Audit, tax, and advisory services for employee benefit plans, including defined contribution retirement plans, defined benefit plans, multiemployer pension plans, and health and welfare plans under ERISA, with Form 5500 preparation and DFVC penalty relief support.
• Energy & Related Industries Services Specialized audit, accounting, and tax services for oil and gas operators and investors, including joint interest billing audits, royalty audits, reserve determinations, and acquisition due diligence.
• Individuals & Trusts Services Tax compliance, retirement planning, educational tax planning, family limited partnerships, and business succession planning services for high net worth individuals, complex trusts, and family limited partnerships.
• Manufacturing, Distribution & Commercial Services Audit, tax, and consulting services for manufacturing, distribution, and commercial services companies, including R&D credits, cost accounting, working capital management, and M&A advisory.
• Not-for-Profit Services Audit, review, compilation, single audit, tax-exempt compliance, and financial consulting services for public charities, private foundations, membership organizations, and tax-exempt organizations.
• Private Investment Companies Services Audit, tax, and consulting services for investment companies, venture capital funds, private equity funds, hedge funds, family offices, and real estate investors, including NAV calculations, fair value accounting, and fund organization.
• Real Estate & Development Services Accounting, auditing, tax compliance, and financial consulting services for real estate developers and investors, including acquisition and divestiture due diligence, cash flow forecasts, investment return analyses, and business valuations.
• Technology Industry Services Accounting, audit, and tax services for technology companies at all stages of growth, including R&D credits, Keystone Innovation Zone (KIZ) Tax Credit Program support, and exit planning from startup through acquisition.

Quantifiable outcome

• Highest peer review rating 'pass' achieved through independent peer review
• +1 more outcomes

Named customers5 records

Segments8 records

Ideal customer profiles9 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Partnerships

One partnership is on record.

• AGN InternationalcoreStrategic or Co-development PartnerAGN International is a worldwide association of separate and independent accounting and advisory businesses. Sisterson's membership provides direct access to practical business advice globally and added depth nationally within a structure of trusted relationships designed to deliver high standards at an affordable cost.

Scale indicators4 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• Schneider Downs & Co., Inc. Pittsburgh-based CPA and advisory firm of comparable scale, offering audit, tax, and advisory services with similar industry verticals (manufacturing, NFP, energy, real estate). Most direct comparable given shared headquarters market and practice mix.
• Hill, Barth & King, LLC (HBK): Mid-Atlantic regional CPA firm of similar size headquartered in Pennsylvania, providing audit, tax, and advisory services to closely-held businesses, NFPs, and high-net-worth individuals with comparable industry specialization.
• Maher Duessel: Pittsburgh-based CPA firm specializing in governmental and nonprofit audit, with similar size and overlapping NFP/governmental audit practice; competes for the same Western PA client base.
• Herbein + Company, Inc. Pennsylvania-headquartered regional CPA and advisory firm of similar size and service mix (audit, tax, advisory), with comparable industry verticals including manufacturing, NFP, and employee benefit plans.
• GBQ Partners LLC: Mid-sized Ohio-based CPA and advisory firm with comparable headcount, industry verticals (manufacturing, NFP, real estate), and advisory practice serving closely-held and family-owned businesses.
• Cohen & Company, Ltd. Mid-Atlantic/Midwest CPA and advisory firm of similar scale with audit, tax, and advisory practices serving closely-held businesses, real estate, and investment companies — directly comparable to Sisterson's private investment company and real estate niches.

Broad incumbents

• Plante Moran: Top-20 U.S. accounting and advisory firm with significantly larger scale, overlapping audit, tax, and advisory services across the same industry verticals; represents the broader incumbent competitive set Sisterson competes against for larger mid-market engagements.
• CliftonLarsonAllen (CLA): Large national CPA and advisory firm with overlapping practice areas (audit, tax, advisory) and industry verticals (NFP, manufacturing, real estate, private investment); competes directly for the same mid-market client profile.
• Forvis (formerly FORVIS, DHG merger): Top-10 U.S. accounting firm formed via merger, offering audit, tax, and advisory services with overlapping manufacturing, NFP, EBP, and real estate verticals — represents the consolidated national competitor Sisterson cannot match in scale.
• Wipfli LLP: Top-25 national CPA and advisory firm with overlapping practice areas and industry verticals (manufacturing, NFP, real estate, technology); a broader incumbent competitor for mid-market audit and advisory mandates.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/sisterson-co-llp

Compliance2 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles15 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 Sisterson & Co. LLP