This excerpt taken from the AMZN 8-K filed Sep 18, 2007.
6.4 Restriction on Transfer
Except to the extent that the corporation has obtained an opinion of counsel acceptable to the corporation that transfer restrictions are not required under applicable securities laws, or has otherwise satisfied itself that such transfer restrictions are not required, all certificates representing shares of the corporation shall bear a legend on the face of the certificate, or on the reverse of the certificate if a reference to the legend is contained on the face, that reads substantially as follows:
The securities evidenced by this certificate have not been registered under the Securities Act of 1933 or any applicable state law, and no interest therein may be sold, distributed, assigned, offered, pledged or otherwise transferred unless (a) there is an effective registration statement under such Act and applicable state securities laws covering any such transaction involving said securities or (b) this corporation receives an opinion of legal counsel for the holder of these securities (concurred in by legal counsel for this corporation) stating that such transaction is exempt from registration or this corporation otherwise satisfies itself that such transaction is exempt from registration. Neither the offering of the securities nor any offering materials have been reviewed by any administrator under the Securities Act of 1933 or any applicable state law.
If any securities of the corporation are issued pursuant to Regulation S (Regulation S) of the Securities Act of 1933, as amended (the 1933 Act), the corporation will refuse to register any subsequent transfer of such securities if such transfer is not made in accordance with Regulation S, pursuant to registration under the 1933 Act or pursuant to an available exemption from registration under the 1933 Act.