TOKYO - Japan's Seven & i Holdings , operator of the 7-Eleven convenience store chain, said quarterly operating profit fell by a quarter, missing analysts' estimates, as inflation hit consumer spending in Japan and North America.

The poor showing adds to pressure on the sprawling retailer to demonstrate it can improve corporate value as it fends off a proposed $47 billion buyout offer from Canada's Alimentation Couche-Tard (ACT).

Profit tumbled to 128 billion yen ($810 million) in the three months to end-November, short of an average estimate of 138 billion yen from seven analysts polled by LSEG.

After ACT's bid, the group's founding family started talks to take the company private for an estimated $58 billion, which would be the largest management buyout in Japanese history.

This would allow the group to continue under current management and relieve pressure to offload unprofitable assets. Some analysts have also said it may be a gambit to induce a higher bid from ACT.

The firm has also hastened plans to focus on its convenience store business by selling a range of non-core assets, among them several supermarket chains and specialist retailers.

In October, Seven & i announced it would create a separate business unit - York Holdings - to house 31 subsidiaries, for which it would solicit external investment before an eventual public offering.

Last month, it concluded the first round of bidding for the assets, with private equity giants Bain Capital and KKR each offering over $5 billion, sources said.

Seven & i retained its profit forecast of 403 billion yen in the year to the end of February. Last October, it lowered its forecast from 545 billion yen as inflation looked set to continue to hit customer spending. 

($1=158.1400 yen)

(Reporting by Anton Bridge; Editing by Clarence Fernandez and Edwina Gibbs)