I think Mr Brownbear is correct. Pershing & Co. and Pershing Square Capital are not one in the same.
I believe Pershing is a market-maker. In the old days, I think it was the name for the clearing ("back office") operations of a large brokerage firm. I can't remember whether Pershing & Co. was under the DLJ umbrella or the Alex. Brown umbrella.
I am invested in ABI, and I am optimistic. Whether Mr Ackman has a position, I am happy with my position.
To all readers: ABI is a speculative security, so don't rely on the judgment of anyone but yourself.
GLTA.