If you acquire restricted common stock, the share certificate you receive should be stamped with a "restricted legend”. The legend will indicate that the shares may not be resold in the public marketplace unless the shares are registered with the SEC or they are exempt from the registration requirements. Here is a typical restricted legend:
THE SECURITIES EVIDENCED BY THIS CERTIFICATE MAY NOT BE
OFFERED OR SOLD, TRANSFERRED, PLEDGED, HYPOTHECATED OR
OTHERWISE DISPOSED OF EXCEPT (i) PURSUANT TO AN EFFECTIVE
REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933,
AS AMENDED, (ii) TO THE EXTENT APPLICABLE, PURSUANT TO
RULE 144 UNDER THE ACT (OR ANY SIMILAR RULE UNDER SUCH
ACT RELATING TO THE DISPOSITION OF SECURITIES), OR (iii)
PURSUANT TO AN AVAILABLE EXEMPTION FROM REGISTRATION
UNDER SUCH ACT.