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 - present
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.