After Yahoo Inc. revealed its new logo on Thursday, chief executive officer Marissa Mayer also revealed that the company undertook its first brand overhaul in 18 years without the help of an advertising or branding agency.

In a blog post, Ms. Mayer wrote about her love for branding – along with a plug for Adobe Illustrator – and her involvement in the design process. She worked with an in-house team of four other employees (including one intern), designing the logo over a single weekend this summer.

To those in the agency world, this kind of in-house branding is not welcome news. And it is on the rise.

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According to a new survey from the New York-based industry group, the Association of National Advertisers, 58 per cent of marketers are using in-house agencies for at least some of their marketing or advertising work. That number has risen 16 per cent in the last five years – a trend the ANA says should alarm agencies.

The move is driven mostly "by internal expertise, greater cost efficiencies and quicker turnaround time," according to the ANA.

"We are seeing a seismic, eminently important industry shift between marketers and agencies," ANA president and CEO Bob Liodice said in a statement. "The growth trajectory of advertising agencies is in question as marketers move existing and emerging functions in-house. The emergence of the in-house agency is a potential warning sign for agencies. We urge our agency peers to adapt to this new reality and offer even greater value to avoid gradual disintermediation with clients."

The finding is based on a survey of 203 marketers conducted this spring and summer.

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Perceptions of those in-house agencies are changing.

"For years, in-house agencies were known as being fast and cheap, but not necessarily good," ANA group executive vice-president Bill Duggan said in the release, adding that they are now more often seen as doing good work as well.

More findings from the report: