In a merger update, TNS took the opportunity to reiterate that it believes the merger with GfK is the best future for the company.
It made the comments after WPP had upped its offer to £1.08bn -- a price that one analyst has said is "an excellent deal for TNS shareholders".
In the statement, TNS said: "The board wishes to emphasise that TNS' business is not the media business, nor is it advertising. It provides market information and advisory services. The board believes that the strong growth prospects in its industry will be more than captured by GfK-TNS."
It also hit back at claims made by WPP that it has not had access to all the same documents as GfK, saying that it "has all the financial information on TNS that has been shared with GfK".
The company adds that it does not want to share any further information with WPP as it sees it as a competitor.
The battle between TNS and WPP has entered a mud-flinging phase. The Wall Street Journal quotes Donald Brydon, chairman of TNS, as saying that WPP chief executive Sir Martin Sorrell "wants to screw us up".
In turn, it reports that Sorrell has said that TNS is living in "dreamsville" if it really thinks that that is the motivation behind the offer.
Today, Brydon said: "We are very pleased that the administrative board of the Verein has voted positively in favour of the merger with TNS. We look forward to working with GfK to create an exciting new global force in market research that will be the envy of our peers."