The board is likely to finalise the decision at a meeting to be held this month, the report said. The Nikkei, which also reported the move, said the insurer plans to carry out the buyback this month.

Shares of Japan Post Insurance were up 7% in early trade on Thursday. The company said in a statement late on Wednesday that it had not made any decision on a buyback plan, and had made no announcement on such a move.

Japan Post Holdings declined to comment.

The share buyback would reduce Japan Post Holdings' stake in its insurance unit to 50% or less, from 64% now, the reports said.

Japan Post Insurance is currently governed by a strict privatisation law that requires it to seek government approval for activities such as the launch of new products. Such restrictions would be eased if the holding company's stake falls below 50%.

($1 = 103.4800 yen)

(Reporting by Chang-Ran Kim, Takashi Umekawa, Yuki Nitta and Daniel Leussink; Editing by Chris Reese & Shri Navaratnam)