(Adds details from filing, background on dispute)
BOSTON, Aug 28 (Reuters) - Billionaire investor William Ackman said he was not eager for a proxy contest with Automatic Data Processing and suggested that the board add his three nominees, a settlement proposal that was rejected, a new filing shows.
Ackman, whose Pershing Square Capital Management owns 8.3 percent of the human resources software company, asked on Aug. 17 whether the ADP board would agree to expand by three and add his proposed directors, according to the Monday securities filing.
ADP did not immediately respond to a request for comment.
One board member said "they did not know but would think about the request," said the filing, which reflects Pershing Square's revised proxy solicitation materials. On Aug. 21 the company said the board unanimously declined to nominate any of Ackman's proposed directors.
ADP shares were up 1 cent at $104.60 in morning trading.
The filing was made to update shareholders about a telephone call Ackman had with members of ADP's Nominating/Corporate Governance Committee. He plans to meet with the full board on Sept. 5.
The filing shows Ackman spoke with the board members only hours after making a 3-1/2 hour presentation that detailed the company's shortcomings.
One board member listened to a portion of the call but it was unclear whether the others heard any of it, the filing said. Certain members also had not seen the company's response to Ackman where management said the fund manager had presented "nothing that had not previously been analyzed by the Board and management."
In the roughly three weeks since Pershing Square disclosed its stake in ADP, the company has taken an unusual tack in dealing with one of the industry's most prominent activists.
In a preemptive move, the company issued a news release announcing Pershing Square's stake and saying that Ackman wanted control of the company and to replace the chief executive officer, and asked for a lot more time to do it all.
Traditionally, companies faced with an activist only issue a bland statement saying they welcome shareholders' input.
Ackman painted a different picture in filings and emails released publicly, saying he did not want control, was open to working with CEO Carlos Rodriguez and asked for only a short extension of the nominating deadline to negotiate more in private.
He said companies often benefited from having a large investor on its board. (Reporting by Svea Herbst-Bayliss; Editing by Lisa Von Ahn)