Billionaire Leon Black’s publishing company Phaidon acquired Artspace.com, an Internet startup that sells works by contemporary artists, as investors struggle to figure out how to make money from art online.

Phaidon, a publisher of art and design books, agreed to buy Artspace, the companies said today in a statement without disclosing the price. The deal is the latest in a wave of mergers and partnerships shaking up the Internet art market even as profit in the nascent industry remains elusive.