Our History

Douglas George (D.G.) Sisterson was born in Gateshead, England.
 

 18-year-old D.G. comes to Pittsburgh and soon enrolls at the University of Pittsburgh.

After graduating from college, D.G. joins Peat Marwick, Mitchell & Co. which would eventually become part of KPMG.

D.G. Sisterson is awarded the Seymour Walton gold medal for the highest score nationally on the American Institute of Accountants exam. (Max Sieger - another Sisterson partner - would later be awarded this honor as well.)

D.G. also became a partner at Crowther & Company. Around that time, J.H. Hillman & Sons Company engaged the firm, with D.G. soon becoming the client’s primary contact.
 

On July 1, Douglas G. Sisterson forms D.G. Sisterson & Company along with J.R. Miller and Max Sieger. The Firm's first clients are J.H. Hillman & Sons Company and the DuPuy family. Offices were in the First National Bank Building, which was demolished in 1970 to make way for One PNC Plaza.

• The stock market crashes and the great depression begins.
• The American Institute of Accountants (AIA) sets rules of professional conduct.

The Hillman Company buys the Grant Building out of bankruptcy and moves in – along with D.G. Sisterson & Company – from the First National Bank Building. Sisterson would remain a tenant for 87 years. 

• The U.S. enters World War II.
• The Taft-Hartley Labor Management Relations Act passes and requires labor unions to prepare financial statements.
• The U.S. begins income tax withholding.

• Max Sieger’s son, Ed, joins the Firm.
• The American Institute of Accountants (AIA) becomes the American Institute of Certified Public Accountants (AICPA).

• In 1964, D.G. retires and Max Sieger becomes Managing Partner of Sisterson.
• In 1969, a scholarship is established at the University of Pittsburgh in D.G. Sisterson’s name.
• Congress passes a law allowing CPAs to represent clients before the IRS.
• The Tax Reform Act of 1969 enacts the Alternative Minimum Tax.

• Ed Sieger named Managing Partner of D.G. Sisterson & Company.
• The University of Pittsburgh awards the first Douglas G. Sisterson Fellowship.
• The AICPA rescinds its ban on advertising by public accounting firms.
• The AICPA creates an SEC Practice Section and a Private Companies Practice Section, both with peer review and quality control requirements.

• Sisterson grows significantly, roughly triples in size.
• The Firm's audit practice grows substantially.
• Bill Troup joins D.G Sisterson and Company in 1980; he and three others buy the Firm from Ed Sieger in 1984.
• Dave Simpson is named Managing Partner in 1988.

D.G. Sisterson dies at the age of 96.

• Firm becomes Sisterson & Co. LLP.
• Bill Troup is named Managing Partner in 1997.
• New evaluations and rewards program created.
• Expansion of consulting practice.
• Sisterson admits first female to partnership group.
• Strategic marketing focus initiated.

• Alternate work arrangements introduced.
• Sisterson joins AGN International.
• Firm accolades – one of the '50 Best Places to Work in Western PA' and one of the 'Best Accounting Firms to Work for' in the nation.
• Dress code moves from ‘business’ to ‘business casual’.
• The Sarbanes-Oxley Act is passed, creating the Public Company Accounting Oversight Board (PCAOB) to set public company auditing standards.

• Brad Lusk named Managing Partner in 2013.
• Succession planning focus/orderly retirement of partners.
• Formalization and growth of industry specialties.
• Leadership Sisterson introduced, along with Women’s Initiative and Emerging Leaders group.
• Sisterson recognized as one of the largest, independently owned accounting firms in the Pittsburgh region.

• Debbie Ogrodnik becomes Managing Partner in 2024.
• Firm officially adopts flexible work and "dress for your day" policies.
• The Firm moves to new office space in the Union Trust Building.
• Sisterson named "One of the Best Accounting Firms to Work for" by Accounting Today. 

• Sisterson celebrates 100 years of serving clients.
• The Firm unveils a new logo, honoring its legacy while looking toward the future.