• Welcome to KOS!

    With an over 80-year history, the mid-sized accounting firm of Kessler Orlean Silver & Co., P.C., provides innovative accounting solutions to business owners, executives and managers, private investors, and professionals.

    Our down-to-earth style and practical experience come from a long-time culture of helping people and feeling passionate about doing so!

  • What Sets Us Apart

    We care. Pure and simple.

    ‘Above and beyond’ dedication to client service is our highest priority. Clients tell us they appreciate our accessibility and outstanding service. We believe it’s essential that you receive our close personal attention with prompt answers and new ideas.

    No situation is too tough or too routine. Every challenge is viewed with a fresh eye and resolved with a creative solution.

    By placing our service standards front and center in the way we conduct business, you can expect to receive the highest quality service while we help you improve your business or personal financials.

  • On the surface, accounting firms seem a lot alike. But some stand out from the crowd. So what makes KOS different? Our people. Sincerely caring, really listening, and then putting your outcome ahead of our interests. It’s our exuberant: to put you above all else.


    Based in Deerfield, a Chicago suburb, KOS serves businesses and individuals in multiple states providing business consulting, accounting and bookkeeping, and tax services.

Firm Profile

Learn more about the firm’s people, philosophies, and client service commitment.


Our monthly newsletter is available online and keeps you current on tax and financial matters.

KOS News Ticker

  • Getting out of Credit Card Debt - Do you need a Snowball or an Avalanche? - By: Diana Spatoulas, KOS Senior Accountant - dspatoulas@koscpa.com - Now that 2017 is in full swing, the recent holidays of 2016 may seem like a distant memory. Colorful decorations and bright lights have been packed away and are out of sight. If it has not happened yet, soon a recap of holiday spending will make its inevitable appearance with the arrival... More →
  • Adjustments in Retirement Plan Limits - The IRS has announced its annual cost-of-living adjustments for certain retirement plan thresholds. Due to relatively low inflation rates, the adjustments for 2017 are minimal or nonexistent, as shown below. - Maximum annual dollar benefit for a - defined benefit plan $210,000 $215,000 - Maximum dollar limit on additions to - a defined contribution plan $53,000 $54,000 - Maximum amount of... More →
  • IRS Reminds Tax Payers of Common Scams - As the 2017 tax filing season unfolds, the IRS is reminding taxpayers about phishing and phone scams. Scammers have been contacting taxpayers via live and automated phone call, email, fax, regular mail, and text message. - Here is a list of some of the most prevalent scams to watch out for: - Students and their parents are contacted and demand is made for a fictitious tax such as the "Federal... More →
  • Charitable Contribution Deductions - Jeffrey Arnol, KOS Managing Partner - jarnol@koscpa.com - Most people are aware that contributions to qualified charitable organizations are deductible for tax purposes. That being said, it is important that everyone is knowledgeable about the substantiation requirements for both cash contributions as well as the rules that apply to contributions of non-cash property such as clothing or household... More →
  • KOS Book Club: The Productivity Project - By: Bruce Kreisman, Kathy Stanley, Olga Bernick, Cameron Kinley and Abigail Schaffer - At KOS we recognize that a successful professional utilizes various skills while servicing our clients. The most obvious are technical skills, whether in accounting, auditing, tax or consulting. But a well-rounded professional will also be strong in the so-called "soft skills," things they do not necessarily... More →
"[KOS is] friendly, approachable, and always willing to help me find the answer to a question." - Joan Meyer La James International College