Thomson departed the company on 16 June after serving in the role since January 2016.
HAI Group has appointed Edmund Malaspina as interim CEO and president.
Malaspina joined HAI Group in 1991 and was most recently the chief marketing officer, responsible for business development, corporate marketing, enterprise strategy, as well as industry initiatives and market intelligence.
In a statement, Malaspina said: “I have seen this company take ideas and turn them into reality, and have been fortunate to be a part of the process.”
He added: “The demand for affordable housing will not be dissipating anytime soon; so I look forward to leading the talented team at HAI Group in the creation of innovative ideas to better serve our members so they in turn can serve their community. I thank the Board of Directors for this opportunity and am confident about the future of HAI Group.”
Christine Hart, chair of the HAI Group board of directors, added: “[The board] provides their full support to both Malaspina and all of the employees at HAI Group. Together through hard work and dedication, the future for HAI Group is bright.”