The spokesman says Radtke, an American, was found dead in her home on Feb. 26. Her company, First Meta, said it was "shocked and saddened by the tragic loss.''
First Meta allowed users of virtual currencies such as bitcoin to trade and cash out the currencies.
The future of bitcoin has been under scrutiny since the collapse of the Mt. Gox exchange in Tokyo last month.
Radtke had worked at other tech companies including Apple.
Postings on her Facebook page showed her to be a believer in the potential of virtual currencies.
Last month she linked to an article on entrepreneurs suffering depression, commenting above the link: everything has its price.