Nelson Peltz's Trian Fund Management began a proxy fight to wina board seat at Procter & Gamble Co., characterizing the makerof detergents and diapers as a lumbering giant whose stock hasunderperformed its peers.

Trian will seek a seat for Peltz at P&G's annual shareholdermeeting, according to a proxy filing Monday with the U.S.Securities and Exchange Commission. The firm, which initiallyrevealed its position in February, now holds 37.6 million P&Gshares, or about 1.5%. It's not seeking a breakup of the company ora new chief executive officer, but rather to shake up its“slow-moving and insular” culture, according to the filing.

P&G CEO David Taylor is struggling to reignite sales growthat the maker of Tide laundry detergent and Pampers diapers asit faces assaults from cheaper rival brands and retailers that arekeeping a tighter rein on inventory to defend themselves fromonline competition. P&G shares are showing a 5.1% total returnfor shareholders since the start of the year, trailing gains of 29%for Unilever in local currency terms, and 12% for Colgate-PalmoliveCo., according to data compiled by Bloomberg.