Osram, whose stock closed up 14.46 percent to reach its highest level in 10 weeks, said the private equity groups, who declined to comment on their interest, are looking at whether to jointly bid for up to 100 percent of its shares.

"The company is currently engaged in detailed discussions with the interested parties. It is not yet clear whether there will be an investment by Bain Capital and Carlyle Group," Osram said in a statement, adding that the talks could fail.

Osram, with a market value of around 3.4 billion euros (2.99 billion pounds), was once part of Siemens and mainly sells its products to car manufacturers.

Bloomberg, which earlier reported the joint bid interest, said in November that Bain was exploring a bid, while the Financial Times reported in December that Carlyle was also a potential bidder.

(Reporting by Irene Preisinger in Munich; Writing by Tom Sims and Christoph Steitz; Editing by Jane Merriman and Alexander Smith)