Nov. 15 (Bloomberg) -- The spot prices of polysilicon, the raw material used in most solar panels, declined 8.6 percent in the past week, Bloomberg New Energy Finance data shows.

The average selling price, which has been falling since August, dropped to $30.19 per kilogram in the week through Nov. 14, according to the London-based research firm’s survey.

Polysilicon makers such as Renewable Energy Corp. ASA and Wacker Chemie AG have seen spot prices tumble 62 percent since March as subsidy cuts reduced demand for solar panels in Europe, the world’s biggest market. At the same time, manufacturers have ramped up production capacity.

To contact the reporter on this story: Alex Morales in London at amorales2@bloomberg.net

To contact the editor responsible for this story: Reed Landberg at landberg@bloomberg.net