* Danone has so far declined to comment on Peltz moves
* CFO spoke about 2013 margin pressure at seminar - analyst
PARIS, Nov 16 (Reuters) - Activist investor Nelson Peltz wants to increase his stake in French food group Danone PA> to gain a say in its management, the Wansquare website said on Friday, without citing its sources.
Peltz and Danone could not immediately be reached for comment. At 1035 GMT, Danone shares were up 0.9 percent at 48.75 euros, among the top gainers on the Paris CAC-40 index.
Peltz, co-founder of U.S. investment firm Trian Fund Management LP, said last week it bought a 1 percent stake in Danone, the world's largest yoghurt maker.
The billionaire, who often wrestles with management at companies he considers undervalued or poorly run, has said Danone was undervalued and should implement cost cuts and other measures to boost its stock price.
Danone, which this week is holding an investor seminar in Russia, has so far refrained from reacting to Peltz' comments.
Few details have emerged from the seminar which is closed to the press.
Credit Suisse, however, said in a note on Friday that Danone Chief Financial Officer Pierre-Andre Terisse had told investors that Danone faced similar margin pressures in 2013 as in 2012.
"Exactly what this means is open to interpretation, but another 50 basis points margin decline in 2013 year on year would be a 'prudent assumption' in our view," the analysts said.
Danone issued a surprise profit warning in June after Spanish consumers switching to cheaper yoghurts hit growth at its core dairy division.
It warned at the time that its 2012 operating margin would decline by 50 basis points to 14.2 percent.