According to Law360 -- The U.S. Supreme Court is poised to decide three weighty tax cases in 2015 that could implicate:

• How states assess income taxes,
• Whether taxpayers can challenge state tax reporting requirements in federal court, 
• How discrimination is defined in federal tax statutes,
• As well as a high-profile transfer pricing case and 
• 2 economic substance cases.

Here are some of the cases Tax Attorneys, Tax Accountants & CPA's should be following:

1. Comptroller of Maryland v. Wynne - In 2015, the U.S. Supreme Court is set to decide the constitutionality of a Maryland law that allows residents with out-of-state income to offset their state income taxes but doesn’t apply to county taxes, in a case that could significantly narrow states' taxing authority if the high court squashes Maryland's current regime.
2. Direct Marketing Association v. Brohl -So-called Amazon taxes have sparked litigation across the country, and in Direct Marketing Association v. Brohl the question before the Supreme Court is whether aspects of Colorado's tax law are protected from challenges in federal court. A ruling in favor of Colorado could make it nearly impossible for businesses to challenge state tax administration practices in federal court and get answers that apply uniformly across jurisdictions.
3. Alabama Department of Revenue v. CSX Transportation Inc. - The federal Railroad Revitalization and Regulatory Reform Act is a highly specific piece of law meant to shield the rail industry from discriminatory sales and use taxes, but an upcoming Supreme Court ruling in a dispute between CSX Corp. and the Alabama Department of Revenue could determine how courts generally define discrimination in tax statutes.
4. Amazon.com Inc. v. Commissioner of Internal Revenue - Amazon is bitterly locked in a $1.5 billion transfer pricing dispute with the Internal Revenue Service over an arrangement it inked with a European subsidiary, and the outcome of the case, which is sitting in U.S. Tax Court, is being closely watched by multinationals and tax lawyers alike.
5. Salem Financial v. U.S. and AIG v. U.S. - BB&T Corp. and American International Group Inc. are currently fighting the IRS in two separate cases, denying that transactions they used for foreign tax credits lack economic substance. And tax attorneys are closely watching the litigation, which is pending before federal circuit courts, to see if the IRS will be able to successfully expand its economic substance doctrine.