Advent Valuation Advisors has been providing valuation, economic damage analysis, and business consulting services to the business community since 1991.

Our clients turn to us for accurate, reliable appraisals for financial and tax reporting, litigation, and planning. Our valuation expertise, in-house or through our extensive network of industry and asset specialists, encompasses all classifications of tangible and intangible assets.



William Quackenbush

With 40 years of business experience, Mr. Quackenbush is a director at Advent Valuation Advisors and holds several valuation-related credentials, including the Accredited Senior Appraiser (ASA) in Business Valuation, the Master Certified Business Appraiser (MCBA), the Business Certified Appraiser (BCA), and the Accredited in Business Appraisal Review (ABAR).  Mr. Quackenbush has provided expert witness testimony for the past 20 years in both Federal and New York State Supreme Court and also before the American Arbitration Association and in mediation cases.

Mr. Quackenbush is a national instructor in Business Valuation for both the American Society of Appraisers and the Institute of Business Appraisers, and he is the author of one of the ASA’s credentialing courses and texts in Business Valuation.

He served as the Chair of the ASA’s Business Valuation Committee and is serving or has served on the ASA’s international education and strategic planning committees. He has also served on the Education Committee of the IBA; served as the technical reviewer of the AICPA’s book on business valuation, “Valuing a Business” (both 3rd and 4th editions), a contributing author of “IFRS Fair Value Guide: The IACVA International Handbook” published in April 2010 by John Wiley and Sons, Inc, and a contributing editor of the Financial Valuation and Litigation Expert. He speaks regularly on business valuation issues, having taught Continuing Legal Education credits on the subject, as well as Continuing Education credits to appraisers and certified public accountants, including teaching in-house business valuation courses to “big four” accounting firms – both in the U.S. and overseas – as well as to the Chinese Appraisal Society in Beijing. Click here for Formal CV of William Quackenbush.

Lorraine Barton

Ms. Barton has an extensive and varied accounting, valuation and restructuring background in private industry, consulting and public accounting. She provides valuation and litigation support services to numerous closely held businesses and public companies for purposes including mergers and acquisitions, solvency opinions, buy-sell agreements, estate and gift tax planning and compliance matters, divorce, and corporate planning and reorganizations. She has also provided transaction-related consulting services to clients on both the sell-side and buy-side of transactions.

She is also the firm’s bankruptcy/troubled company expert, assisting manufacturing, distribution and retail clients with bankruptcy and restructuring, and has advised both debtor and creditor institutions and has experience in a variety of industries.

Lorraine specializes in providing turnaround and crisis management, financial advisory and litigation support services to distressed and underperforming businesses by bringing practical solutions to companies through her experience in cash management, financial analysis, financial forecasting, interim management, creditor negotiations, and restructuring plan development and execution. Lorraine is a Certified Public Accountant and a member of the National Association of Certified Valuators and Analysts (NACVA) and holds the Certified Valuation Analyst (CVA) valuation credential from them. She is also a member of the Association of Insolvency and Restructuring Advisors, earning their Certified Insolvency Restructuring Advisor (CIRA) designation, as well as a member of the American Institute of Certified Public Accountants. Click here for Formal CV of Lorraine Barton

Elaine Onischuk

Ms. Onischuk possesses comprehensive experience in the public accounting, private business, government, and non-profit sectors encompassing forensics and litigation support, business valuations, fraud detection and prevention, advisory, tax, private business and non-profit accounting and financial reporting, compliance, and training and development services. She has provided fraud detection, and litigation and business valuation support services to clients for shareholder dispute, buyout, acquisition due diligence, bank fraud, insurance claims, estate and gift tax planning, and matrimonial purposes. In her role as a former IRS agent, she conducted examinations of NY Metropolitan area businesses with domestic and international operations, detecting fraud, and locating concealed and disguised transactions, relationships, businesses, and assets.

Elaine is a Certified Public Accountant in New Jersey and New York (pending), is certified in Financial Forensics, and possesses the CFE credential. She is a member of the American Institute of Certified Public Accountants (AICPA) and the Association Certified Fraud Examiners (ACFE).

Ms. Onischuk has provided expert witness testimony in New Jersey courts and also in mediation cases. In addition to her accounting experience, Ms. Onischuk possesses over ten years of experience in the training and education sectors.

Formal CV of Elaine Onischuk