Wrong. A successful prosecution against ME will result in...

Wrong. A successful prosecution against ME will result in financial penalties against the corporate entity. BOQ owns ME and will be responsible for paying those penalties unless that contingent liability was specifically carved out in the sale documents. I am not aware of any deal of this kind where a vendor would agree to remain liabile for a contingent liability, nor any purchaser willing to accept an indemnity from the vendor for the same. The reason is obvious: BOQ bought ME warts and all. What assets do the vendors retain to secure that indemnity? Nothing. BOQ owns those assets.

TLDR: BOQ (and therefore its shareholders) will end up paying any criminal fine. BOQ may have a civil action against the former directors (and therefore their D&O insurance policies) as well as any advisers on the transaction if ME failed to fully disclose the extent of the misconduct during the due diligence phase. The previous announcement from BOQ stated that it was aware of this risk at the time of buying ME, so that possible action seems unlikely at this stage.