Common shares aren't assets - the high bidder was bidding on assets - not common shares.
The company buying the assets couldn't care less about the common shareholders - the high bidder has no legal, ethical or moral obligation to shareholders.
The BioAmber management is responsible for being incompetent in operating the company - but rest assured they did very well before resigning.
IG
"Are you gonna pull those pistols or whistle Dixie?"