Art sales at public auction often make headlines, but even more expensive art may change hands by private sale. Experts at The Financial Times, a London-based international publication, have consulted knowledgeable sources around the world and come up with a list of the Top 10 Most Expensive Paintings ever sold. Some of them, including Edvard Munch's "The Scream," were sold at auction while others went quietly behind the scenes.

The list, published June 23, comes with cautions. Nothing has been officially announced and many of the sources are informed by nothing but their "nose" and the "process of elimination," wrote Julia Sutherland.

The identities of buyers are uncertain since no one is talking, but people in the know say that members of the royal family of Qatar are "some of the biggest players in the market at the moment -- but frustratingly for those who like to make lists, they never confirm or deny a purchase. So although the royal family's supposed holdings are now as fabled as Ali Baba's cave, we do not actually know what they have bought, or where they keep it, or even what they intend to do with it," the FT wrote.

That said, here's the FT's "reasonably authoritative" list:

1) "The Card Players" (1892 - 93) by Paul Cezanne. Sold 2011. Likely buyer royal family of Qatar. $250 million.

2) "No. 5, 1948" (1948) by Jackson Pollock. Sold 2006. Unknown buyer. $140 million.

3) "Woman III" (1953) by Willem de Kooning. Sold 2006. Buyer Steven A. Cohen. Price $137.5 million.

4) "Portrait of Adele Block-Bauer I" (1907) by Gustav Klimt. Sold 2006. Buyer Ronald Lauder, Neue Galerie.135 million, British pounds.

5 ) "Portrait of Dr. Gachet" (1890) by Vincent van Gogh. Sold 1990. Buyer Ryoei Saito. Price: $82.5 million.

6) "Bal du moulin de la Galette" (1876) by Pierre-Auguste Renoir. Sold 1990. Buyer Ryoei Saito. Price: $78.1 million.

7) "Garcon a la pipe," (1905) by Pablo Picasso. Sold 2004. Likely buyer Barilla group. Price: $104.2 million

8) "The Scream" (1895) by Edvard Munch. Sold 2012. Likely buyer royal family of Qatar. $119.9 million.

9) "Nude, Green Leaves and Bust" (1932) by Pablo Picasso. Unknown buyer. $106.5 million.

10) "Orange, Red, Yellow" (1961) by Mark Rothko. Sold 2012. Unknown buyer. $86.9 million.