1978 to 2000 - Principal of Mark Kesner, CPA PC., where Mark was responsible for the management of the accounting firm, financial statement preparation and review, tax preparation, tax planning, and compliance providing expert witness testimony. In addition, Mark was responsible for adding financial planning and estate planning services to the practice.

1977 to 1978 - Employed as Chief Accountant & Director of Finance for GRI Computer Corporation, a computer manufacturing and OEM company. GRI was a publicly traded company. Responsibilities there included preparation of monthly financial statements, organization of workpapers for the outside auditing firm, Arthur Anderson & Company, and preparation of 10-Q, quarterly compliance reports required to be sent to Securities & Exchange Commission. Other responsibilities included the overseeing of the accounts payable and accounts receivable departments, and cash management services with State Street Bank.

1972 to 1977 - Employed by William Gabovitch & Company, a medium size CPA firm. His position led him to be Accounting Manager in charge of a staff of six. Clients of the firm were broad based including the following industries: medical, retail, legal, manufacturing, hotels, nursing homes, and construction. Responsibilities included preparation of financial statements, tax preparation, tax defense and compliance, and planning issues.