WPP said today that the sale of a majority stake in data analytics business Kantar is on track and that its full-year outlook was steady. 

The world's biggest advertising company had shortlisted a series of US buyout funds to submit binding bids for a majority stake in Kantar as it looked to finalise the sale in late June, Reuters reported in May. 

Private equity firms Bain Capital, Apollo and Platinum have made it through to the final stages of the auction along with a fourth, undisclosed, bidder, sources had told Reuters. 

Kantar generates about 15% of WPP's overall sales and provides brand and marketing communications research for some of the world's largest advertisers. 

WPP did not give further details on the progress of Kantar's stake sale. 

It chief executive Mark Read had said in March that the group would see particularly strong headwinds in the first half of 2019, with the whole year expected to be down between 1.5-2%. 

Read hopes to bring WPP back in line with peers by the end of 2021. 

WPP, the owner of agencies including JWT, Finsbury and Ogilvy, is also in the middle of an overhaul launched by Read after several profit warnings in 2017 and 2018. 

"Our new business performance this year has been solid, with GroupM in particular maintaining its successful record in pitches," Read said in a statement after the company's annual meeting today.