Sard Verbinnen & Co. is working with Automatic Data Processing Inc. as it rebuffs activist investor Bill Ackman's demand to dump CEO Carlos Rodriquez and take half of the 10 board seats at the $12.4B payroll/taxes/benefits administrator.

Ackman's Pershing Square Capital Management, owners of an eight percent stake in Roseland, NJ-based ADP, wants an extension of the Aug. 10 deadline to nominate directors to the company's board.

ADP

ADP claims Ackman first contacted it on Aug. 1 with his request to extend the deadline for up to 45 days.

The company says while it's open to "constructive criticism," the 2017 deadline has been public for a year and changing it would not be in the best interests of shareholders.

"We believe our current Board has an effective balance of leadership continuity and fresh perspectives that will help us to continue this strong track record of delivering value to shareholders," said ADP's statement.

ADP also touted the leadership of Rodriguez, noting a 202 percent in total shareholder return during his six years of leadership.

SV&C's George Sard, Liz Zale and Jared Levy represent ADP.