GfK majority owner denies considering stake sale

* GfK Verein says boards have no plans to approve sale

* German magazine had said it was eyeing a sale or merger

* GfK Verein: Will do everything it can to support GfK (Swiss: GFK.SW - news)

* Shares (Berlin: DI6.BE - news) drop 3.8 pct to bottom of SDAX index (Adds shares, further GfK Verein comment, background)

FRANKFURT, Aug 26 (Reuters) - The majority owner of German market research firm GfK said on Friday it was not considering a sale of shares, rejecting a magazine report that had said it was eyeing a merger or sale of the group.

"The bylaws of (majority owner) GfK Verein show that a share sale is not easily done, as the executive board and the advisory board would have to approve such a plan, and they are not doing that," GfK Verein President Hubert Weiler said in a statement.

German weekly WirtschaftsWoche reported on Thursday that GfK's U.S (Other OTC: UBGXF - news) . rivals Nielsen Holdings (Frankfurt: NHL.F - news) and IMS Health (Frankfurt: A1XFVF - news) as well as WPP (Frankfurt: A1J2BZ - news) unit Kantar were interested in GfK Verein's 56.5 percent of GfK.

GfK Verein's denial on Friday pushed the shares down 3.8 percent to 28 euros, wiping out the previous day's gains and making them the biggest decliners on Germany's small-cap index .

GfK's stock has fallen by 20 percent this month after it warned on 2016 profits for a second time and its chairman and chief executive both unexpectedly resigned due to a falling-out with GfK Verein over strategy.

GfK on Thursday named a new chairman from the ranks of its majority owner, who GfK Verein said on Friday had already started to analyse the situation at the group.

"GfK Verein is backing GfK for the long run and will do everything possible to ensure the company returns to a sustainably successful path," GfK Verein's Weiler said. (Reporting by Maria Sheahan; editing by Victoria Bryan and Jason Neely)