Swiss food group Nestle SA was downgraded to market-perform from outperform on Tuesday by Sanford C. Bernstein, the first time it has changed that rating since it began covering the stock in February 2002. Analyst Andrew Wood said the shares are fully valued and cash generation was disappointing. "Nestle's stock has 'benefitted' from the perfect storm of weak markets and a strong Swiss franc," said Wood. But he said the downside of the strong franc is that it "significantly dilutes Nestle's earnings per share," and the investment firm expects EPS growth in 2011 and 2012 of 9% and 10% respectively on constant currencies, but negative 7% and growth of 3% on current foreign exchange. The 12-month price target on Nestle was dropped to CHF52 from CHF64.