I am standing in a private dining room on the seventh floor of the London offices of UBS, the global financial services firm. A table is set for lunch, with a menu promising bresaola with caponata followed by roast lemon sole. Before the powerful guests arrive, though, I am whisked away. As I go, my eye is drawn to some art hanging on the wall: a pair of rare, large watercolors by the contemporary Danish artist Olafur Eliasson. These are just two of the 32,000 objects that make up the UBS Art Collection, which includes paintings, photographs, drawings, prints, video works and sculptures from the last 50 years.

Corporate art collections are hardly a new phenomenon. In the late 1950s, the American plutocrat David Rockefeller decided that Chase Manhattan Bank should start acquiring art.