We’ve confidentially submitted an S-1 to the SEC for a planned IPO. This Tweet does not constitute an offer of any securities for sale.

— Twitter (@twitter) September 12, 2013

My initial response was mostly a shrug. Twitter had been widely expected to go public in early 2014, so a confidential filing now would fit that time-frame. I even said as much earlier this evening on CNBC, mindful that not even 100 of the 250+ confidential filers have even submitted public S-1s. All we really know, I added, is that the company has less than $1 billion in annual revenue.

But my nonchalance may have been misplaced.

A source close to the company says that we should see an actual S-1 from Twitter within the next several weeks, and that today’s announcement was more about legal maneuvering than it was about controlling its own press. Remember, Twitter didn’t say that it filed confidentially today. It said today that it had filed confidentially. See the distinction? My understanding is that the original filing was submitted a  while ago, and that most of the SEC review is completed.

Moreover, Twitter would expect to launch its road-show exactly 21 days after the S-1 is filed, which would be its minimum waiting period (some companies wait months, if not years). In other words, this is designed to be a 2013 offering rather than a 2014 offering.

We do not yet know if Twitter has picked an exchange on which to list, although sources suggest it has not. There is a report that Goldman Sachs (GS) has been picked to be lead underwriter, and another that Twitter has been fielding hedge fund offers at a valuation of around $14 billion (which is a major bump from the $10 billion it was getting in private trades over the summer).

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