I'm curious - why only "if the Lifull deal fell through"? $12,000 put down today on 20,000 MUA shares will net you $4,000 profit if the deal does go through... a 30% return.
If your wife and two kids had Commsec accounts, you'd gross $16k profit (tho' it's understood if they are under 18, the kids would get hit with a 45% tax bill)
