ArtNet
http://www.artnet.com
Contains over two and a half million auction records from more than 500 auction houses worldwide.
Subscription required for full database.
Artprice
http://artprice.com
Contains information on over 300,000 artists and features over 21 million auction prices and indexes. Also includes biographical information and 36,000 signatures, monograms and symbols.
Subscription required for full database.
AskART
http://www.askart.com
Contains information on over 35,000 artists. Includes auction records and artwork for sale.
Subscription required for full database.
Invaluable
http://www.invaluable.com
Contains pre-sale and post-sale information for sale houses across United Kingdom, Europe, North America and Canada.
Subscription required for full database.