The deal, which values College Group at around £45 million, is thought to have been finalised late last week and will be announced to the City on Monday morning.
Vitruvian will take a majority stake in the group, with existing management and staff retaining a substantial equity investment in the business.
As a result of the deal, College Hill founder Alex Sandberg will step down from his role as group chairman, handing day-to-day management of the group to CEO Richard Nichols. Sandberg will remain a significant shareholder and will focus on working with and advising clients in the financial PR and business comms practice.
Sandberg told PRWeek that the deal 'sets the seal on the work we've done over the past four years'.
Over this period, the group has grown from its financial PR roots to acquire and establish practices in public affairs, employee engagement, research, branding, design, reporting and digital.
College Group currently employs more than 300 people in 13 owned offices in Europe, Africa, Asia and the US, with an annual turnover of £40 million.
Sandberg commented: 'I’m really proud of how we’ve built College Hill into the group it is today, with the broader range of services for our clients and our increasing international reach. Fresh capital from a blue chip investor adds a game-changing dimension to our ambitions. I believe our greatest potential still lies ahead of us and I’m backing Richard and the team to deliver the next stage.'
Nichols, who joined College Hill in 2006, said that the Vitruvian deal would enable the group to concentrate on further international expansion, building a stronger presence in the US, Europe and emerging markets.
Nichols said the group had 'ambition to be one of the select few international business communications consultancies serving the world’s leading organisations'. He added: 'We have the platform, the team and a focused ambition. And we now have access to the capital to accelerate our plans.'
Vitruvian completed fundraising for a €925 million fund, the Vitruvian Investment Partnership, in 2008.
It is not thought that there is any debt in the College Group transaction.
Toby Wyles, managing partner at Vitruvian, said: 'We want to invest in high quality companies that have focused, proven business models and very talented people, who don’t want to sell out but need capital to realise their ambitions. That’s our role, to provide the fuel for growth. In College Group, we’ve invested in a company that’s absolutely in our sweet spot. We look forward to our partnership with College Group shareholders, helping them to continue to realise the full potential of their business.'
College Group was formerly wholly owned by a group of 132 shareholders, primarily current employees of the business.
Vitruvian was founded in 2006 by former partners of Apax Partners, BC Partners and Bridgepoint Capital. It invests in Northern European businesses in industries characterised by growth and change such as information technology, media, telecoms, financial services, business services, healthcare and leisure.