Minebea Co., a maker of miniature ball bearings, at the end of September will liquidate two subsidiaries in the United States and Singapore as part of operational restructuring.

The U.S. subsidiary is NMB Air Operations Corp. in Nevada, which has been operating a DC-10 plane to transport materials to plants in Thailand and Singapore from Japan since 1995, Minebea said. It is being liquidated because the plants can procure the necessary materials locally.

The Singapore subsidiary is NMB Precision Tool & Die (Pte.) Ltd, which produces machine tools and other equipment for Minebea's overseas plants, the Tokyo-based company said. It will be absorbed by NMB Singapore Ltd. to streamline operations.

Losses from the liquidation of the two subsidiaries were included in Minebea's business results in the just-ended fiscal year.