History

1926   
On July 1, D.G. forms D.G. Sisterson & Company along with J.R. Miller and Max Sieger. First clients are J.H. Hillman & Sons Company and the DuPuy family. Offices are in the First National Bank Building, which is demolished in 1970 to make way for One PNC Plaza.

1929 

• The stock market crashes and the great depression begins.

• The American Institute of Accountants (AIA)  sets rules of professional conduct.

1937   
The Hillman Company buys the Grant Building out of bankruptcy and moves in – along with D.G. Sisterson & Co. – from the First National Bank Building.

1940s

• 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.

1950s

• Max Sieger’s son, Ed, joins the Firm.

• The American Institute of Accountants (AIA)  becomes the American Institute of Certified  Public Accountants (AICPA).

1960s

• 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.’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.

1970s

• 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.

1980s

• Firm grows significantly, roughly triples.

• Audit practice grows substantially.

• Bill Troup joins Firm in 1980; he and three others buy the Firm from Ed Sieger in 1984.

• Dave Simpson named Managing Partner  in 1988.

1990s

• Firm becomes Sisterson & Co. LLP.

• Bill Troup named Managing Partner in 1997.

• New evaluations and rewards program created.

• Expansion of consulting practice.

• Firm admits first female to partnership.

• Strategic marketing focus.

2000 - 2010

• 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.

2010 - 2020

• Brad Lusk named Managing Partner in 2013.

• Succession planning focus/orderly retirement  of partners.

• Formalization and growth of niche teams.

• Leadership Sisterson introduced, along with Women’s Initiative and Young Professional Group.

• Sisterson recognized as one of the largest, independently owned accounting firms in the Pittsburgh region.

2020 - present

• Debbie Ogrodnik becomes Managing Partner in 2024.

• Firm officially adopts fully-flexible work policy.

• Sisterson moves to the Union Trust Building.