• 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

  • What’s the Tax Payoff from Gambling? - Losses may offset annual winnings - Do you enjoy the thrill of gambling? Whether you end up winning or losing, it is important to understand the main tax rules related to your gambling activities. Otherwise, you may end up owing considerably more tax than you normally would have to pay. - Background: On the federal level, gambling winnings constitute taxable income. It does not matter how and... More →
  • How to Safeguard Your Computer Network - Steps for improving security measures - Would you ask a salesperson to hold onto your wallet or pocketbook while you go shopping in their store? Of course not. Yet, in effect, some small-business owners are doing virtually the same thing with their computer networks when they conduct business online. It is almost like giving hackers a license to steal your money. - What are the potential dangers?... More →
  • Managing Your Finances the Easy Way - Lais Gruman Castello, Accounting Services Staff - As a young professional in the accounting field, I understand the importance of keeping accurate records and forming good financial management habits. There are many free online tools available to help you feel confident managing your money, such as LearnVest and Mint.com. - First, why use one of these programs and what do they do? Ostensibly, to... More →
  • KOS is Hiring! - Help us spread the word! We are actively seeking exceptional candidates for the following positions: - Tax Interns to work next busy season; February to April 15, 2018 - Temporary Front Desk Receptionist; August 28th to October 16, 2017 - KOS will be on-campus during the month of September for interviews and attending career fairs at the following schools: University of Illinois at Chicago (UIC),... More →
  • RSVP Today! - Fifth Annual KOS Women’s Professional Empowerment Event - Thursday, September 28th - 8:00-10:30am - Come learn from three dynamic women who enable effective leadership, inspire, and help people gain focus. - Katrina Calihan – Leadership Coach - Tammy Cook – Business/Life Coach - Lee Ann Piano – Corporate Trainer - Chevy Chase Country Club - 1000 N. Milwaukee Avenue, Wheeling, IL -... More →
"[KOS is] friendly, approachable, and always willing to help me find the answer to a question." - Joan Meyer La James International College