Glass Lewis recommends ADP investors vote for Ackman's slate

BOSTON, Oct 23 (Reuters) - Proxy advisory firm Glass Lewis said on Monday that it recommends Automatic Data Processing shareholders vote for all three dissident directors, giving activist investor Bill Ackman a boost in a bitter proxy battle with the company.

Glass Lewis, which advises large institutional investors, is the first advisory firm to issue its findings before the November 7 vote.

"Glass Lewis finds validity in (Bill Ackman's firm) Pershing Square's overall thesis and we have determined that a sufficient basis exists to support the Dissident's solicitation for minority representation on the ADP board," the firm said in its report.

(Reporting by Svea Herbst-Bayliss)