Mr Cartwright will be working at the financial research group as head of insight.
He had worked at Bluefin for eight years, being particularly involved with corporate due diligence and research activity within the firm.
He joined as a director with Destini and Thinc before they were bought by AXA and rebranded as Bluefin.
He has worked in the financial services industry as a whole for over 30 years.
At his new role in Defaqto he will responsible for producing the company’s industry publications and product ratings.
Kenn Herskind, chief executive of Defaqto, said: “David’s wealth of senior level experience and in-depth understanding of the financial services sector will further strengthen our ability to lead the market in financial product data collection, analysis and management.”
Mr Cartwright said: “The insight team is a key unit within Defaqto, which supports the business’s key audiences in many ways through expert product and industry analysis. I look forward to helping support the company’s broad customer base which includes product providers, intermediaries and the public sector.”
The move follows an earlier announcement this month that John Simmonds had resigned from his position as chairman of Bluefin Corporate Consulting and Bluefin Wealth Management.