I'm thinking the delayed filing/total silence is because of something material. Definitely not because of impending doom.
I couldn't find the exact law for the U.S. (I'm not patient enough to search the SEC database). I borrowed this from our neighbors to the north, and I believe the same applies for U.S. companies:
(1) Securities legislation permits a company to delay disclosure of a material change and to keep it confidential temporarily where immediate release of the information would be unduly detrimental to the company's interests. For example, immediate disclosure might interfere with a company's pursuit of a specific objective or strategy, with ongoing negotiations, or with its ability to complete a transaction. If the harm to a company's business from disclosing outweighs the general benefit to the market of immediate disclosure, withholding disclosure is justified. In such cases a company may withhold public disclosure, but it must make a confidential filing with the securities commission.
