Two days after Procter & Gamble Co. (PG) management defended its stewardship of the company, activist shareholder Nelson Peltz's firm wrote a blistering letter to shareholders of the consumer products company advocating that he be added to the company's board. 

Trian Fund Management LP, which as of July 31 held a 1.47% stake in P&G worth $3.45 billion, said Wednesday, Aug. 16, that P&G's letter contained "false and misleading statements" in its defense of its "lackluster" operating and stock performance. The firm was particularly critical of P&G CEO David Taylor's contention that Peltz's board service at other companies did not create shareholder value.

"The addition of a motivated independent director who has a material ownership stake and substantial relevant industry experience can be a valuable resource for overcoming the root causes of these challenges and helping to create the right environment for breakthrough ideas," Trian wrote. "To be clear, Nelson has no hidden agenda. His only agenda is to improve performance so that P&G can increase returns to all shareholders and create long-term shareholder value."

Shareholders will vote on Peltz's addition to the board at P&G's annual meeting on Oct. 10. Trian took its P&G stake in February. Shares are up 9.7% year to date, below the S&P 500's 10.1% increase during the same period.

Peltz currently sits on four boards: Wendys Co. (WEN) , Mondelez International Inc.  (MDLZ) , Sysco Corp.  (SYY) and Madison Square Garden Co.  (MSG) .

In its Tuesday letter the firm also quoted a number of CEOs that Trian has worked with in the past, including Ed Breen of DuPont (DD) .

P&G products.
P&G products.

Breen, a breakup specialist, becameDuPont's CEO in 2015 after the abrupt resignation of Ellen Kullman. Kullman won a proxy fight against Peltz, objecting strongly to his plan to split DuPont into parts. While it was Peltz's first-ever loss, Kullman's departure and the company's subsequent plan to merge with Dow Chemical Co. (DOW) and then split the $75 billion company into three vindicated Trian's efforts.

Taylor had also suggested that Peltz was disingenuously and inaccurately criticizing the company in public while privately suggesting to management that he was "supportive" of the company's progress. "We believe Mr. Peltz initiated this proxy contest to satisfy his own agenda and to meet the expectations of his limited partners," rather than benefiting all shareholders.

"In a misguided effort to keep Nelson off the Board, P&G management has mounted a massive defense and estimates it will spend approximately $35 million of your money - which we believe, in reality, will amount to at least $100 million - on multiple mailings to P&G shareholders and payments to at least nine advisors," Trian countered. "Imagine what all that money could do if it were invested in regaining lost market share - instead of paying for four investment banks, at least two law firms, two proxy solicitors and a PR firm, that P&G has hired to keep one highly qualified shareholder out of the P&G boardroom."

Among those expenditures, revealed in an Aug. 1 proxy filing, is $2.5 million to proxy solicitors D.F. King & Co. Inc. and Mackenzie Partners Inc. P&G expects to spend $35 million on the proxy solicitation process and to date has spent $950,000. Trian expects to spend $25 million on the proxy fight.

P&G and Trian did not immediately respond to requests seeking comment.

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