Shares of Shake Shack (NYSE: SHAK) are lower Monday as traders and investors focus on an upcoming lock-up expiration on the evening of November 10th.

On October 8, the company filed a prospectus relates to the offer and sale from time to time by the selling stockholders identified in this prospectus of up to an aggregate of 26,160,694 shares of Class A common stock, par value $0.001 per share, of Shake Shack Inc. Out of the 26,160,694 shares of Class A common stock that our selling stockholders may offer and sell, (i) 5,124,114 restricted shares of Class A common stock previously have been issued to certain of our stockholders and (ii) the remaining 21,036,580 shares of Class A common stock will be issued by us from time to time to certain other of our stockholders who are also holders of LLC Interests (as defined herein) upon the exchanges by such stockholders of an equivalent number of LLC Interests (and the surrender and cancellation of an equivalent number of shares of Class B common stock, par value $0.001 per share, of the Company) held by such stockholders.

The filing created some confusion, as it was bringing class B to class A. In fact, JPMorgan analyst John Ivanhoe asked about it on the company's recent conference call:

Q (John Ivanhoe, JPMorgan) - Understood. And a final one for me. Hopefully, there are all small enough questions. I think there was some confusion in the press around your registration for the shares bringing class B to class A. You didn't mention it really in your prepared remarks. But is there anything that you would like to clarify in terms of what that means? When that stock could be sold by the existing shareholders? Is there any lockups that we should be sensitive to blackout periods, what have you, in terms of when that stock could be in the public market?

A: (Randy Garutti, CEO) - Well, thanks for asking that John. I appreciate it. Giving us a chance to clarify that. I think there was some misunderstanding of that. Let me direct you first of all, the best information you're going to get is the registration statement that's on file with the SEC. But I will say, we believe -- the reason I was doing it, is there's efficiency to achieve by us registering the class A shares at once. We have a unique upsea structure here, okay? That registration allows any pre-IPO owner to sell from time to time as they might choose. It is not an indication of anything more than that. This filing does not overshadow the confidence of Danny Myer, our Board, our Management, myself, our Directors have in the long-term outlook of this business.

Once effective, the float is expected to increase from about 9.75 million shares to 35.9 million.

Despite the expiration, the company points out the shares are not tradable until they are registered pursuant to an effective registration statement no earlier than November 12.

Shares of SHAK last traded down 4.3% to $47.85.