TA Associates, which has raised £23.7bn in capital since its inception, invests in companies around the world that it believes demonstrate opportunities for strong sustainable growth.
It has backed 25 wealth and asset management firms worldwide.
Fairstone said the additional funding will be used to expand its acquisition activity.
The amount of the investment has not been disclosed.
Current private equity backers Synova have also reinvested into the group.
Asset management firm and existing funders Alcentra have also increased the scale of acquisition facilities available to the Financial Planning firm.
Lee Hartley, CEO of Fairstone, said: “The combined expertise and backing of TA, Synova and Alcentra means we have a deeper and wider foundation than ever before. We’ll use this foundation as a platform to do more deals with an emphasis on ambitious firms that are on a clear upward trajectory. We’re not looking to simply consolidate steady-state businesses – we want to invest in growth.”
He also said the senior leadership team of Fairstone has re-committed to at least another five to 10 years with the Financial Planner and have invested “a significant proportion of their capital” back into the firm.
Fairstone will continue as a Newcastle-headquartered business with a major London operation, serving clients from regional offices across the UK.
The Financial Planning firm completed 10 acquisitions in 2020 and expects deal volumes to rise in the coming years to support its aspirations.
In January Fairstone acquired Berkshire-based Hammett and Petch Financial Planning for its first deal of 2021 under its downstream buyout acquisition model. The acquisition secured gross fee income of £800,000 for Fairstone together with funds under management of over £60m.
Other recent acquisitions for Fairstone include South West-based Sabre Financial and South Wales-based UskVale Financial Planning in December.