Sisterson Timeline

Built on Decades of Trust

Sisterson & Co. LLP at 90 Years


1920   D.G. becomes partner at Crowther & Company. J.H. Hillman & Sons Company employs Crowther, with D.G. becoming the primary contact soon after.

  D.G. speaks and approves of Andrew W. Mellon’s income tax plan.

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.

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

1930s - 1950s

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.
  • 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).

1960s - 1980s

Max Sieger1960s
  • 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.

  • 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.
  • 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.


  • 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 - present

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.