Filing: Ackman sold about 5M ADP shares and options after defeat

With a board battle lost, Bill Ackman"s Pershing Square sold about 5M shares and call options in Automatic Data Processing (NASDAQ:ADP) in December.

That leaves the firm with about a 7.2% stake, according to an SEC filing, down from 8.3%.

Ackman"s said he might go back to the proxy-fight well in a year if he doesn"t see dramatic improvement in operations.