Catherine A. Tanck

Catherine A. Tanck

South Dakota Tax Attorney

My Story

South Dakota lawyer Catherine A. Tanck is a CPA and tax attorney at Davenport Evans. Cathy’s practice is focused on taxation, real estate, corporate and business law, banking and financial services, and estate planning and probate and trust administration.

Cathy Tanck has received an AV Preeminent® Peer Review Rating by Martindale-Hubbell®, for the highest level of professional excellence in legal knowledge, communication skills and ethical standards. She was recognized by Best Lawyers® as a 2020 Lawyer of the Year in Mergers and Acquisitions Law, and was named in the areas of Business Organizations (including LLCs and Partnerships); Closely Held Companies and Family Business Law; Litigation and Controversy – Tax; and Tax Law. She is also listed in Great Plains Super Lawyers in Tax; Closely Held Business; and Mergers & Acquisitions.

Position: Partner
Direct: (605) 357-1223

Professional Experience

Davenport, Evans, Hurwitz & Smith, LLP 
Partner: 1992 – present
Associate: 1988 – 1991 

Law Clerk to Honorable Roger L. Wollman, U.S. Court of Appeals, Eighth Circuit 

McGladrey & Pullen, LLP 

Certified Public Accountant, South Dakota


Augustana College 
(B.A., Accounting and Economics, summa cum laude, 1979) 

University of South Dakota School of Law 
(J.D., Sterling Honor Graduate, 1987)

Professional Memberships

State Bar of South Dakota
Minnehaha County Bar Association
American Bar Association
American Institute of Certified Public Accountants
South Dakota CPA Society
Minnesota Society of Certified Public Accountants


Admitted to Practice (State): 
South Dakota, 1987 

Admitted to Practice (Federal): 
United States Court of Appeals, Eighth Circuit, 1988
United States Tax Court, 1989


Joseph N. Spencer II Award, Best Contribution to South Dakota Law Review, Volume 31

Topics Editor, South Dakota Law Review, 1986-1987

Order of Barristers
Moot Court Board

Author: Depreciation of the Core Deposit Intangible: A Tax Incentive to Acquire a Failed Bank, 32 South Dakota Law Review 80 (1987)

Author: Investment Tax Credit: A New Test for “Inherently Permanent,” 31 South Dakota Law Review 800 (1986)

Co-Author: Impact of Reagan’s Tax Proposal on Agriculture, 31 South Dakota Law Review 309 (1986)

Protecting what you’ve built.

Phone Numbers

Driving Directions

Davenport Evans, Hurwitz & Smith, LLP

206 West 14th Street
P.O. Box 1030
Sioux Falls, SD 57101-1030