riddle me this, page-7

I agree with you JMcDog; you're basically on the mark but a few other factors kick in as well as the individual's tax position and brokerage rates etc.
1/ There is the risk that the share price of SXY will fall and cancel out the apparent arbitrage
2/ and of course there is the risk that the important clause re: 50.1% of STU shares must accept the offer, is not fulfilled during the offer period, then the offer may lapse leaving the arbitrageur with only STU shares and no SXY shares
I will not comment on the 'risk' or likelihood of either possibility but be aware these things may happen and other possibilities no doubt exist like another TO offer muddying the waters and delaying a result for an extended period. So do your own research and assess the risks yourself sotirib.