ADP said recent communications with Pershing Square Capital Management indicate the company seeks to take control of it through the acquisition of five board seats.

The change -- along with naming a new CEO -- would be made at ADP’s annual meeting in March. According to a press release by the collective, Pershing first contacted ADP on Aug. 1 and William Ackman said it beneficially owns 8 percent of ADP.

Ackman requested that ADP extend the Aug. 10 deadline for nomination of directors by several weeks. He planned on nominating himself and four other board directors.

"ADP is open to constructive input from our shareholders, and our Board respects the right of shareholders to nominate directors,” ADP said in a press release. “However, ADP has a clearly defined Board nomination process, and the 2017 deadline for director nominations has been public for nearly a year. The Board has unanimously determined that it is not in the best interests of ADP or its other shareholders to accede to Pershing Square's last-minute request for an extension.”

ADP is receiving financial advice from Morgan Stanley & Co., while legal actions are being dealt with by Paul, Weiss, Rifkind, Wharton & Garrison LLP.