• 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

  • Tax Pros and Cons of Municipal Bonds - Balanced view of investment tax aspects - Municipal bonds (often called “munis” for short) may be attractive to high-income taxpayers, but there are a number of potential tax drawbacks as well. Here is a brief look from both sides of the fence. - Tax Pros of Munis - First, and most important, the interest income is exempt from federal income tax. For example, if you earn a 4% return on a... More →
  • Employers' Beware of New Form I-9 and Employment Eligibility Verification Rules - All US employers must ensure proper completion of Form I-9 for each individual they hire for employment in the United States. This form is used to verify the identity and employment authorization to work of all paid employees. It includes citizens and noncitizens. The form is not required for unpaid volunteers or for contractors. - You may not be aware that a new newly revised version of the I-9... More →
  • Four Top Retirement Plans for Self-Employeds - Weigh all retirement plan options - At one time, pension plans and other qualified retirement plans were usually offered only by larger companies, but now, many small companies have caught up. In fact, if you are self-employed with just one or two employees—or maybe just yourself—you still have plenty of retirement plan options at your disposal. Here are four popular choices for self-employed... More →
  • RSVP Today! - Fifth Annual KOS Women’s Professional Empowerment Event - Thursday, September 28th 8:00 -10:30am - This Year’s Speakers Are: - Katrina Calihan – Leadership Coach - Tammy Cook – Self Management Coach - Lee Ann Piano – Leadership Trainer & Coach - Chevy Chase Country Club - 1000 N. Milwaukee Avenue, Wheeling, IL - Breakfast Buffet Will Be Served - Cost: Free - RSVP by September 12th -... More →
  • Understanding Installment Sales - Jeffrey Butler, Director - jbutler@koscpa.com - Most of us are not familiar with how an installment sale works. An installment sale is a transaction structured whereby the seller receives payments over a period of time rather than all at once. It can be beneficial to both the buyer and seller. In addition to making it easier for the buyer to afford making the purchase, an installment sale can... More →
"[KOS is] friendly, approachable, and always willing to help me find the answer to a question." - Joan Meyer La James International College