It is interesting to me that AMBS is not doing 3 offerings (one for each sub).
This would allow AMBS to remain a full reporting company and allow investors to buy into the specific technology that they believe in.
Could be cost prohibitive for the company to do 3 offerings at this point.
Or it could be that they don't want a situation where one of the subs (e.g., the MANF sub) raises tons of money and the others don't.
A wholly owned subsidiary of an Exchange Act reporting company parent is eligible to complete a Regulation A/A+ offering as long as the parent reporting company is not a guarantor or co-issuer of the securities being issued.