OSAKA (Kyodo) The founding family of Kyorin Holdings Inc. is not planning to sell its shareholdings in the medium-size pharmaceutical company, sources said Tuesday, casting doubt on a bid by major generic drug producer Sawai Pharmaceutical Co. to acquire it.

The family owns roughly 40 percent of Kyorin shares, traded on the Tokyo Stock Exchange's first section. Sawai, believed to have already acquired a stake of slightly less than 5 percent in Kyorin, has proposed turning Kyorin into a subsidiary by increasing its stake.

Hiroko Ogihara, a former Kyorin chairman, and Minoru Ogihara, her predecessor, said in their recent shareholdings reports with financial regulators that the founding family and a related company agreed Sept. 17 not to sell their stakes for a certain period of time.

Sawai has given the Kyorin side until Thursday to decide on its acquisition offer.

Kyorin posted consolidated sales of ¥99.76 billion in the fiscal year ended in March, roughly double those of Sawai, which had group sales of ¥50.07 billion in the same period.