Lyndon Sommer

Shareholder in St. Louis, MO

Lyndon Sommer, B.S. (Acct.), M.Acct., Registered CPA (Ill.), J.D., is a shareholder of Sandberg Phoenix & von Gontard.  The majority of his work is devoted to defending professional liability cases. 

Lyndon specializes in defending accountants in professional negligence cases. He has successfully defended accountants at trial and on appeal.  Lyndon has defended accountants in cases pending in Missouri and Illinois state courts.  In addition, he has successfully defended accountants in federal court.  Lyndon has defended accounting professionals well over 100 cases. Lyndon has defended Certified Public Accountants facing Complaints filed in front of the Missouri Board of Accountancy.  This work includes clients practicing in Missouri and other states.

As part of his professional liability practice, Lyndon has defended attorneys and financial advisors in litigation and arbitration.  He has also defended professionals in the construction industry. 

Lyndon is a member of the Missouri Society of CPAs and the American Association of Attorneys/Certified Public Accountants.

Before he began practicing law, Lyndon authored numerous tax articles which were published in legal and accounting journals including the Practical Accountant, Taxes – The Tax Magazine, Taxation for Lawyers, The Review of Taxation of Individuals, North Dakota Law Review and Southern Illinois University Law Journal.   In addition, he co-authored the first chapter of a book entitled, How to Deal with the IRS.

He has tried cases in federal and state courts in Missouri and Illinois. Lyndon has received jury verdicts on behalf of plaintiffs and defendants.  He has also argued multiple cases before the United States Courts of Appeal for the Seventh and Eighth Circuits, as well as the Illinois Appellate Court and Missouri Court of Appeals.

Lyndon earned his Juris Doctor at Southern Illinois University School of Law in 1992, where he was the Editor in Chief of the Southern Illinois University Law Journal.  He earned a Masters degree in Accountancy in 1989 and a B.S. in Accounting, in 1987 from Southern Illinois University, Carbondale.


Product, Asbestos & Toxic Tort Liability Professional Liability Commercial Litigation


Accounting Architects & Engineers Brokers / Dealers & Financial Advisors Construction & Development Entrepreneurs, Closely Held & Family Owned Business Lawyers & Law Firms Manufacturing & Distribution Restaurants Transportation Wholesale & Retail Services