Possible Clues:

• Capital head of industry invested in furniture
• Union in the European capital
• Oprah in "The Color Purple"
• Queen of Spain's Juan Carlos I
• World capital at the foot of Mount Vitosha
• One of the Coppolas
• Capital I invested in Chesterfield?
• Capital needed in very short order
• Capital of island protected by South Africa
• European capital whose name is Greek for 'wisdom'