As expected, WPP Group is making a hostile bid for audience measurement firm Taylor Nelson Sofres, which has rejected the ad holding company’s three previous offers, Reuters reports. That in turn, has led UK-based TNS’ preferred suitor, Germany audience measurement provider GfK to rethink the combination of equals that was originally being worked out in May. That deal has been valued at €100 million ($154 million) and would create the globe’s second-largest audience measurement firm behind Nielsen. Now, GfK says it is considering a cash offer for its UK rival.

As it stands now, WPP is now bidding £1.8 billion ($2.13 billion) for TNS, which met the deadline handed down by the London Stock Exchange takeover panel. Analysts are uncertain whether a cash offer from GfK would ignite a bidding war between it and WPP.

The Guardian: GfK is seeking additional funding to be able to go ahead with a cash offer for TNS. WPP’s goal is to merge TNS with its own audience reseacher, Kantar, would create savings of more than £50 million ($98.6 million) annually.

• TNS Rejects Latest WPP Offer, Deadline Stopclock Begins To Tick
• WPP’s TNS Bid - Can Sorrell Count On A Rebel Within?
• WPP’s Sorrell On TNS/GfK: ‘Two Drunkards Propped Up By A Lamp-Post’
• WPP Expected To Bid Higher For TNS; Sorrell: Rejection Was ‘Cavalier’; TNS: Offer Was ‘Derisory’