TOKYO (Reuters) – Shares of Japan’s Seven & i Holdings fell by almost 6% in morning trade on Tuesday, giving up some of their gains from the previous day, when they surged on news of a takeover proposal from Canada’s Alimentation Couche-Tard.

While the value of the offer has not been disclosed, it would make the 7-Eleven owner the largest-ever Japanese target of a foreign buyout. Couche-Tard owns the Circle-K chain of convenience stores.

Seven & i said Couche-Tard has proposed buying all of its outstanding shares, while the Canadian company confirmed a “friendly proposal” was sent to Seven & i, adding it was focused on reaching a mutually agreeable transaction.

Seven & i shares were down 5.7%, after losing more than 12% shortly after the open. On Monday, the news of the deal sent the company’s shares surging by almost 23% in Tokyo, valuing the retailer at around 5.6 trillion yen ($38 billion).

Couche-Tard, which operates Circle-K convenience stores, is valued at roughly $58 billion.

($1 = 146.2800 yen)