Short-term market inefficiency

I noticed something interesting about a week ago.  At 1:51 PM on Sept 2 or Sept 3, a Schedule 13-D was filed by Perry corp indicating it had taken an additional 3 million share position in JC Penney.  Just after 2:00 PM, JC Penney jumped about 40 cents, or 3%.  It is interesting that, even with the high-frequency trading that is rampant today, it took about 10 minutes for the market to react to that public information.