Miguel Cotto and Canelo Alvarez were pretty quick to come to an agreement to fight each other at a 155lb catchweight, a comfortable weight for both men. What appears to be the last remaining issue is settling on a venue for the fight, with several viable options on the table.
Of those options, there is an offer from the MGM Grand in Las Vegas, The Wynn also in Vegas (which would partner with the Thomas & Mack Center), and Cotto's beloved Madison Square Garden in New York City. ESPN's Dan Rafael reports that the offer from the MGM Grand and Wynn/Thomas & Mack are both multimillion-dollar guarantee ticket buys with an allotment of rooms and food credit (but Rafael reports the MGM's offer is worth at least $1M more).
Taking the MGM deal would make the fight on November 7th, which apparently is not the preference of HBO. With the Wynn/Thomas & Mack deal, the fight would be held on November 21st, a date that both HBO and Miguel Cotto prefer. The Madison Square Garden offer would also make the fight on November 21st, but with a guarantee of $6M in cash, not tickets, which means the promoters would get the money and keep the rights to sell the top floor seats.
Cotto apparently is willing to fight wherever the most money is (because that's what's best for Miguel Cotto and his family), but Golden Boy appears to prefer the fight to take place in Vegas rather than NYC, even if MSG does offer higher guaranteed money. Their contention is that even with less of a guarantee in Vegas, they believe the fight can still generate more money overall in Las Vegas (which I'm sure has nothing to do with not wanting to fight in Cotto's adopted backyard).
Of course tax implications are always a thing to consider. Canelo prefers the fight to happen in Vegas because his tax liability would be much less significant than it would be in NYC - which is a completely understandable and fair point. I would imagine that would also have to be an important consideration for Miguel Cotto as well. One way or another though, it appears that the two sides will be able to work something out and my hunch would be that Las Vegas will be the choice.