Mark Rothko's 1969 "Untitled" via Artnet

On November 14, 2007 – the peak of the global contemporary art frenzy – Sotheby’s sale included a cerebral 1969 black and misty gray Mark Rothko, painted just one year before the artist ended his life.

“Untitled,’’ a sophisticated acrylic on canvas, was estimated to fetch $12 million to $18 million, coming just one season after the spectacular results achieved by the lavender and tangerine Rockefeller Rothko which fetched an historic $72.8 million.

The black and gray Rothko was being sold anonymously, but dealers identified Des Moines collectors John and Mary Pappajohn as the sellers. The estimate was bold, especially for a late Rothko with such a somber palette.

Nevertheless, dealers say it was one of the Las Vegas collecting brothers, Lorenzo and Frank Fertitta, who snapped up the painting for $12.1 million including fees. The Fertitta brothers are known for their taste for Warhol, Basquiat and Hirst.

The pair made a fortune with their bloody gladiator-style UFC (Ultimate Fighting Championship) franchise. Other investments haven’t panned out as well. Last month Station Casinos, which they inherited from their father, filed for bankruptcy with $5.7 billion in assets and $6.5 billion in debts, according to Bloomberg News.