The new entity will employ more than 500 employees globally, with the addition of 225 members of staff from Blue Rubicon and 30 from StockWell.
The deal, concluded last night, will see the parties immediately start collaborating on financial and corporate reputation management issues. The aim is for the London operations to be combined and co-located in the "near future", reporting to Teneo International chairman Charles Watson.
Fraser Hardie, senior partner at Blue Rubicon, told PRWeek that Blue Rubicon and Teneo may "potentially" start working on the same accounts. They currently have some clients in common in their different territories, such as Coca-Cola and McDonald’s.
The deal will see all members of the Blue Rubicon and StockWell senior management team stay on as part of the Teneo leadership team.
Blue Rubicon, founded 15 years ago, operates across offices in London, Doha, Dubai and Singapore and is understood to have an annual fee income of around £25m. Its major clients include Tesco, British Gas, HSBC and eBay. The agency was named Large Consultancy of the Year in the 2014 PRWeek Awards.
London-based StockWell, founded in 2010, is led by managing partners Tim Burt, Philip Gawith and Richard Holloway. It specialises in providing boardroom-level strategic communications advice to leading corporations and individuals across the UK, Europe and beyond.
"The acquisition of Blue Rubicon and StockWell is a transformational moment for Teneo as we continue to grow across the globe, building on our reputation as one of the world’s leading advisory firms," said Declan Kelly, chairman and CEO of Teneo.
"Teneo is fortunate to advise many of the world's most senior business leaders on a daily basis. This requires us to be able to provide the highest-level strategic counsel at all times. Today’s acquisitions will help us to enhance Teneo’s offering even further in this regard.
"Both Blue Rubicon and StockWell are world-class businesses with great leadership, tremendous clients and highly respected teams and cultures. The synergies between our businesses will position Teneo to support our clients with the highest level of strategic advisory services and provide many new opportunities across all 12 of our operating divisions."
Hardie said: "We are incredibly excited about becoming part of Teneo. We’re bringing together a compelling combination of skills to meet growing demand for reputation-related advice at a time when CEOs and boards look increasingly to manage reputation more strategically and across the whole enterprise. Many now see the systematic growth of trust as providing the oxygen in which to do business - a vital element which maintains strategic freedom, accelerates transitions and cements competitive advantage."
Gawith said: "Teneo has built a business of significance and scale advising chief executives and the opportunity to build on this success in the UK and beyond is very exciting. This is even more true in combination with Blue Rubicon, a firm whose leadership we have known and respected for many years.
"Together we have the opportunity to build an integrated and differentiated reputation advisory offer that will prove very compelling to clients."
Speaking to PRWeek after being named CEO of Teneo International in January, Watson emphasised the firm’s desire to grow and said expansion "could include acquisitions as well as building organically".
Teneo was founded in 2011 by Kelly and Douglas Band, the top comms adviser for former US President Bill Clinton, as well as Paul Keary, a former senior MD of FTI Consulting. Clinton and former UK Prime Minister Tony Blair had served on the advisory board for the group. Teneo operates across 12 offices globally.