Charles A. Koss



As one of the firm’s senior trial attorneys, Charles Koss has nearly three decades of experience representing individuals, small businesses and major corporations in real estate, property, employment, estate and trust litigation, and winery litigation.  He has extensive experience in state and federal courts, as well as administrative, regulatory and enforcement proceedings.  Mr. Koss’s courtroom know-how, combined with his accounting background, gives him a unique ability to analyze and solve his clients’ legal problems.  He is effective in settling disputes where a business resolution can be found and, when necessary, will fiercely protect his clients’ legal interests in court.  He has earned Martindale-Hubbell’s “preeminent” AV rating and the repeat business of many satisfied clients.  Mr. Koss is also the managing Shareholder of the firm.

Mr. Koss represents a diverse group of real estate clients, from individual brokers, buyers and sellers to national brokerages.  He specializes in disputes that arise out of the purchase and sale of real property, including nondisclosure, misrepresentation, breach of fiduciary duties and enforcement of purchase agreements.  Working closely with the firm’s land use group, he has litigated numerous disputes over easements, right-of-use, nuisance and zoning. 

Through his longstanding relationship with his small business clients, Mr. Koss has developed an expertise in all aspects of employment law.  He advises employers and employees about their legal options and counsels businesses on risk management and litigation avoidance techniques.  He has represented clients in arbitration and before governmental agencies with jurisdiction over the employment relationship, including the California Labor Commissioner and the California Fair Employment and Housing Commission.

Although an experienced transactional attorney, Mr. Koss is often sought out by the firm’s diverse practice groups to help posture clients in impending litigation matters.  He has developed a niche in winery litigation, representing vineyard owners and closely-held wineries in a broad range of business matters, including grape-quality issues, non-payment and shareholder disputes.  He is also experienced in estate litigation, representing clients who are contesting or defending a will or trust or disputing the administration of an estate.


Mr. Koss attended the University of Wisconsin, earning his Bachelor’s Degree in Accounting in 1975.  He successfully completed the Uniform Certified Public Accounting Examination the same year.  Mr. Koss attended Boalt Hall School of Law at the University of California, Berkeley, obtaining his Juris Doctor in 1981, and became a member of the California State Bar the same year.


Mr. Koss is a member of the California State Bar Association, the Contra Costa County Bar Association, and the Business Section of the California State Bar. He is also a member of the American Bar Association’s section on Corporation, Banking, and Business Law, the California Trial Lawyers Association, and is an Associate Member of the Wisconsin Institute of Certified Public Accountants.


Mr. Koss is actively involved in the community, particularly with advising nonprofit entities.

He lives in Diablo.