• Long, multidisciplinary career on Wall Street including 14 years at Merrill Lynch 
• Contributing writer, Investopedia
• Author, "Career Confidential: An Insider's Guide to Business"
• Consultant to independent entrepreneurs, editor of academic research papers in economics, developer of materials for an ESL course aimed at business professionals and university students.

During his 14 years at Merrill Lynch, Mark was a major contributor in many areas, most notably:

• profitability analysis
• transfer pricing 
• business forecasting 
• product pricing 
• sales compensation 
• market research 
• data mining
• business strategy

Prior to Merrill Lynch, Mark developed a comprehensive sales forecasting system for AT&T, before moving into project analysis. Then he became a management consultant at Touche Ross (since merged into Deloitte), whose engagements included merger analysis, forensic accounting, bank operations and mutual funds accounting.

Self-employed since 2001, Mark's activities have included being a strategic advisor to an Internet entrepreneur, a consultant to banking giant JPMorgan Chase, a guest lecturer at New York area colleges and an editor of academic research papers in economics. In his book Career Confidential: An Insider's Guide to Business (2008) Mark draws case studies in career management from his own experiences. He also has been interviewed for television documentaries dealing with the functions of the DTCC and financial fraud committed against Hollywood's elite. Additionally, Mark is a contributor to Investopedia, "the world’s largest digital financial education platform."