Ukranian billionaire Viktor Pinchuk has revealed he was a major buyer at Damien Hirst's record-breaking $200 million Sotheby's sale last month, but has declined to say exactly what he purchased. Pinchuk, who's worth an estimated $5 billion, has his own museum in Kiev, the first private institution of its kind in the former Soviet Union, which already houses works by Hirst, Jeff Koons and Vuitton collaborator Takashi Murakami. He says he plans to display his new Hirst acquisitions at the Pinchuk Center in the spring.

"Victor Pinchuk is having a great impact on the [art] market," Simon de Pury, chairman of auction house Phillips de Pury & Co., who credits him with starting the oligarch art collecting trend, tells Bloomberg. "The contemporary art market in both Ukraine and Russia has really taken off in the past two years, and I expect this growth to continue." Earlier this year Pinchuk paid a record $150 million for a house in London, the world's most expensive at the time.