WPP today reported a 0.8 percent dip in Q3 revenues to $4.8B as CEO Mark Read promised "decisive action and radical thinking" to turn around the ad/PR combine.

That bold action includes reviewing strategic options for Kantar, the No. 1 data, insights and consulting unit.

WPP's lackluster financials sparked a sell-off as its US shares are down 18 percent to $57.45.

Read said WPP faces "structural change, not structural decline" and was hindered in the past for being too slow to adapt, overly complicated and under-invested in core parts of the business.

He's developed a plan to simplify the organization, invest more in creative talent, establish a common data and technology strategy and make it easier for clients to access offerings throughout WPP.

Read is soliciting partners for Kantar to unlock the full potential of the research giant.

He expects WPP will remain an investor in Kantar with strategic links to ensure clients benefit from its expertise.

WPP has suffered a recent string of major client losses including Ford creative and American Express, HSBC, United Airlines and GSK for primarily media work.

It's defended BP, Mars, Shell, T-Mobile, Mondelez and Adidas.

A weak North America market hurt WPP's Q3 performance as the $1.9B unit posted a 1.5 percent drop in reported revenues.

WPP's PR unit (Hill+Knowlton Strategies, Ogilvy, Finsbury, BCW Group), also lagged, registering a 0.5 percent gain in reported revenues to $385M.

The group was up 2.6 percent on a like-to-like basis.

Read also announced the retirement of group finance director Paul Richardson, who will exit next year after 23 years of service to the company.