TA Associates acquired a "significant minority" stake in Apex Group, a global financial services firm with $1.1 trillion in assets under administration and custody.
Terms of the deal were not disclosed.
Apex is majority-owned by private equity firm Genstar Capital.
"With TA Associates as a new partner, we look forward to continuing on our growth trajectory and further enhancing our capabilities," said Peter Hughes, Apex founder and CEO, in a news release announcing the deal.
M. Roy Burns, managing director of TA Associates, added in the news release: "We have been extremely impressed by Peter Hughes, his team, and the principles they champion. They have achieved a global leadership position for Apex and continually build on the partnership they maintain with their clients. We are aligned with Apex management's vision for the future and look forward to pursuing their global business model with Genstar and being a key partner in supporting Apex's platform as they develop new services and strengthen their tech-enabled services."
Representatives from TA, Genstar and Apex could not be immediately reached for additional information.
Morgan Stanley & Co. and Macquarie Capital advised Genstar on the deal, while Willkie Farr & Gallagher served as Genstar's legal adviser. Goodwin Procter was legal counsel to TA Associates.