The shares gained 4.5 per cent to 1,027 yen, the highest since July 10, at the 3 pm close of trading in Tokyo.

Olympus, the Japanese endoscope maker that admitted to accounting fraud last year, fell 1 per cent, while Japan's benchmark Nikkei 225 Stock Average declined 0.4 per cent.

Sony will invest about 50 billion yen (€486 million) in Olympus and set up a company to manufacture medical equipment, public broadcaster NHK reported September 14.

Olympus chairman Yasuyuki Kimoto said in July the Tokyo-based company was in discussions with Sony, Terumo and Fujifilm about possible tie-ups.

"It would be a good purchase for Sony," said Kenichi Hirano, general manager and strategist at Tachibana Securities in Tokyo.

A tie-up would help Sony expand its medical business, he said.

Sony hasn't made any decision and wasn't the source of reports on the talks, the Tokyo-based company said in a statement on September 15.

Mami Imada, a Sony spokeswoman, declined to comment when reached by phone today.

Olympus hasn't narrowed down candidates for a capital alliance, Tsuyoshi Oshima, a company spokesman, said September 14.

A deal between the two companies may be reached within a month, the Nikkei newspaper reported September 15, without saying where it got the information.

Bloomberg