A growing number of companies from outside the advertising industry are looking to snap up ad agencies amid a takeover frenzy because of the digital boom, a report suggests.

Digital agencies made up nearly half of merger and acquisition deals across the global marketing services industry last year, according to the corporate finance firm Clarity.

“Non-traditional buyers are increasingly active in the market,” said Clarity partner Marcus Anselm, referring to the consulting firms PwC, Deloitte and Accenture, printing groups St Ives and Communisis and the US talent agency William Morris.

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“We believe this trend will only accelerate,” added Mr Anselm, who said companies from outside the ad industry want to expand because digital marketing is a growing sector and technology means everything is becoming more measurable and automated – a trend dubbed “ad tech”.

Consulting firms, which often have a global client list that is similar to the big ad groups, see an opportunity to “move further up the value chain” by offering not only advice but also execution, said Mr Anselm. Private equity investors are also acquisitive as they are sitting on cash piles.

Last July’s Publicis and Omnicom mega-merger to create the world’s largest ad group affected M&A deals. The total number fell from 127 in 2012 to 116 last year, but that was still up on 2010 and 2011.

Clarity said a “chasm” has opened between the “Big Two”, Publicis Omnicom and WPP, and the smaller groups Interpublic, Dentsu and Havas, which are under pressure to play “catch-up”.

Most observers expect further consolidation, but Mr Anselm suggested there is “a limited amount of speculation left to do” and some ad groups will look to “buy outside the sector”. For example, WPP could consider buying a consulting firm, he said.

Clarity, which advised on the £36m sale of Walker Media to Publicis, said valuations are at their highest since 2007.