There is no disclosure duty for a voluntary non-public SEC investigation (see below). I suspect that is why it was not previously disclosed. I suspect it was disclosed in the SC 13E3 because most attorneys will advise your to disclose everything and the kitchen sink in this filing since this filing is the preliminary step in the shareholder voting process on the acquisition. From a trading perspective, someone who wanted to get some shares below $25 likely fed the story to the media. I agree with the first post that it was stupid for anyone to sell on this news. Good time to buy though.
"On March 14, 2012, the SEC informed the Company that it was initiating a non-public investigation into whether there had been any violations of the federal securities laws related to the Company (the “SEC Inquiry”). The SEC advised the Company that the existence of the investigation should not be construed as an indication by the SEC or its staff that the Company or any of its officers or directors had violated any of the federal securities laws.
As part of its investigation, the SEC requested that the Company voluntarily provide certain documents and other information. The Company agreed to voluntarily cooperate with the SEC and, through its legal counsel, has been cooperating with the investigation by providing the SEC with documents and information as well as having its legal counsel meet with the SEC."