It seems that UFC president Dana White's issues with The Palms Casino Resort have led to the UFC no longer holding events in the venue, according to the Las Vegas Review Journal. Apparently, the falling out was caused by White's credit line being cut in half by the casino earlier this year. He was a big spender in various areas of the resort including their N9NE Steakhouse, and was known as a huge tipper. Once his credit was cut, White pulled all Zuffa events out of there.
The Palms had hosted almost all of The Ultimate Fighter Finales and a few UFC Fight Nights as well over the past five years. Strikeforce had run there a couple of times as well when they were still holding Challengers events after the Zuffa purchase. The last event Zuffa ran there was The Ultimate Fighter 15 Finale on June 1st. The TUF 16 Finale will go down in the Hard Rock Hotel and Casino instead.
The Casino Resort has reportedly been hit very hard by the recession, and this surely won't help. White is well known for his gambling, and he has spoken about it on multiple occasions. Pulling Zuffa business out of a casino that cut his credit line seems a bit much, but I'm sure not getting the full story right now. For what it's worth, White apparently declined comment on the issue.