NEW YORK -- The co-founder of Energy Conversion Devices Inc., a maker of solar cells and fuel cell batteries, exercised options for 23,000 shares, according to a Securities and Exchange Commission filing Tuesday.

In a Form 4 filed with the SEC, Stanford R. Ovshinsky reported he exercised the options for $9.69 apiece Thursday and sold all of them the same day for $33.75 to $34.02 apiece.

Insiders file Form 4s with the SEC to report transactions in their companies' shares. Open market purchases and sales must be reported within two business days of the transaction.

Energy Conversion Devices is based in Rochester Hills, Mich.