Actually I suspect AM may be able to argue that since there is no 'ownership' of the company conferred by owning AM shares, that they did not offer securities. This is obviously muddied by the use of the words IPO, share, securities etc.
Clearly you have not read the legal definition of a security, nor have you been around for very long or you would have known better. There is absolutely zero doubt AM shares are legally securities subject to SEC regulation in so far they are offered to US investors.
JOBS Act, Title III.