** Chemical maker's shares down 6 pct at $70.05; biggest drag on S&P 500 and Dow Jones Industrial indexes
** Wins a proxy fight against activist investor Nelson Peltz's Trian Fund Management for board seats
** Says shareholders elected all 12 DuPont director nominees
** Trian, which owns a 2.7 percent stake in DuPont, was seeking four seats on DuPont's board including Peltz
** DuPont has refused to add Peltz to its board
** Trian has for months criticized DuPont's underperformance and demanded to split the company
** Earlier Peltz's Trian said it appeared its nominees were not elected to the DuPont board, saying the vote was close
** "DuPont's board and management team have staked their reputations on executing the Company's current strategy," Trian said in a statement on Wednesday