2025 Tax Calendar
Below is a summary of when various tax-related forms, payments and other actions are due. Please review the calendar and let us know if you have any questions about the deadlines or would like assistance in meeting them.
Explore Practice Areas
Our professionals provide assurance, tax, and advisory services to clients locally, regionally and across the nation.
Audit & Other Assurance Services
Our audit and assurance services identify opportunities to improve accounting information systems, tighten financial control, and, ultimately, enable management to obtain the most accurate information for making strategic decisions.
Tax Services
Our firm is a leader in tax compliance and sophisticated tax planning strategies. The scope of our tax practice goes far beyond routine tax return preparation for businesses, individuals and trusts.
Advisory Services
Our consulting professionals have substantial experience and are committed to providing clients with valuable information to help them make the best business planning decisions.
Industries & Specialties
Utilizing a niche team approach and organizing around your unique industry enables us to develop an in-depth understanding of your business.
Locally Owned, Serving Pittsburgh & Beyond
Sisterson was founded in Pittsburgh, Pennsylvania, and our headquarters is still located downtown in the Union Trust Building. Our firm has lived through the Great Depresson, the rise and fall of the steel industry, and the emergence of the technology sector in our city. We proudly serve clients outside of the region and around the country but we are truly a Pittsburgh-based firm.
A Rich History of Success Since 1926
Today, we we stand atop the shoulders of our founders, our employees, and all of the valued clients we’ve served, as we prepare to usher in our next hundred years. We’re proud of our history. And we’re thrilled about our future.
Firm Culture
One firm, one office, one mission. The employees and partners of Sisterson work out of one office, in the Union Trust Building, in downtown Pittsburgh.
Life at Sisterson
Our collaborative environment, work-life balance and commitment to the non-profit community.
Meet our Team
For 98 years, our professionals have served clients large and small with the same standard of service.
View Open Positions
Sisterson is very interested in recruiting and retaining individuals committed to providing and supporting quality client service.
Featured Blog Posts
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2025 Mileage Rates Announced
On December 20, 2024, the IRS released the optional standard mileage rates for 2025.
Fundamental Differences Between Nonprofit and For-profit Accounting
You may know the difference between nonprofit and for-profit accounting systems, but do your newest employees and board members?
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