The owner of convenience store giant 7-Eleven has received a buyout offer from Canadian rival Alimentation Couche-Tard (ACT), which runs the Circle K chain.
Tokyo-based Seven & i Holdings says it has formed a special committee to decide whether or not to accept the offer.
Shares in Seven & i jumped by more than 20% on the news.
That gave the Japanese firm a stock market valuation of around 5.6tn yen ($38.5bn; £29.7bn).