Upcoming National Meeting Illinois State and Local Tax Update Webinar Join industry tax peers for a timely update on Illinois State and Local Taxes. This live webinar is open to industry tax professionals nationwide who have an interest in Illinois tax.
Legislative Alert ISSUE 26-34; September 30, 2026 Illinois Issues Draft Digital Asset Tax Rules for Public Comment; Federal Cash Rounding Legislation Passes U.S. House, Senate
Cost Conscious ISSUE 26-19; September 18, 2026 Over the past several weeks, our polling has shown that COST members are increasingly using AI in their SALT functions, particularly for state tax research, drafting communications, and summarizing information. At the same time, respondents indicated that AI-generated outputs are generally subject to professional review and verification before being used. Given this measured approach to adoption,
COST - Council on State Taxation Amicus Briefs AT&T Mobility, LLC v. Board of Supervisors of Lamar County, Mississippi COST filed an amicus brief requesting the Supreme Court of Mississippi to accept an interlocutory appeal to address both the legality of, and constitutional issues with, a county assessor’s property tax valuation of a telecommunications company’s personal property. The brief pointed out concerns with the assessor not following the State’s valuation process which for industrial personal property is
COST - Council on State Taxation COST Studies, Articles & Reports Redrawing the Lines: The Evolution of Alternative Apportionment (The Tax Lawyer, Spring 2026) This article, authored by Marilyn Wethekam of COST, traces the constitutional and statutory foundation of fair apportionment and the evolution of the Uniform Division of Income Tax Purposes Act (UDITPA) Section 18 as a statutory mechanism for addressing fair apportionment.
COST - Council on State Taxation COST Comments & Testimony Letter to Request Removal of Provisions Unrelated to Finnigan in Bill 26-708 COST sent a letter to members of the DC Council requesting requesting the removal of provisions in Bill 26-708 that are not necessary for the transition to the Finnigan corporate tax apportionment method