Couche-Tard M&A deal under investigation by U.S. authorities, causing Seven & i Holdings' shares to decline.

• Seven & i Holdings' shares dropped after reports emerged that the FTC might probe a potential deal with Alimentation Couche-Tard.
• Sources familiar with the matter reported that U.S. antitrust authorities requested Seven & i, the owner of 7-Eleven, to preserve all relevant documents for a review following the disclosure of Couche-Tard's $38.5 billion bid for the Japanese retail company in August.

On Wednesday, Seven & i Holdings' shares dropped after news emerged that the U.S. Federal Trade Commission had informed the Japanese retail giant about a potential investigation into a possible deal with Canada's Alimentation Couche-Tard.

During Asia trading hours, Seven & i's shares fell 2.89%. On Tuesday, its shares closed 1.39% lower.

Sources familiar with the matter revealed that U.S. antitrust authorities have requested Seven & i, the owner of 7-Eleven, to preserve all pertinent documents for examination. This comes after Couche-Tard, a Canadian retail company, made a $38.5 billion offer for the Japanese retail company last month.

The FTC was concerned that the companies' defense attorneys were advising them to destroy documents related to the potential merger before antitrust investigations began, according to Reuters. No official notification of a probe has been issued yet.

Antitrust probes into Microsoft, OpenAI, and Nvidia were launched by the FTC and Justice Department in June, while Amazon and Google have also faced recent antitrust investigations.

The owner of 7-Eleven rejected a cash takeover bid from a Canadian convenience store operator last week, stating that the offer was not in the best interest of its shareholders and stakeholders, and citing U.S. antitrust concerns.

If the deal goes through, it will be the largest foreign acquisition of a Japanese company. Seven & i announced that Couche-Tard had offered to buy all outstanding shares for $14.86 per share.

According to Tokutaka Ito, partner at A&O Shearman, a law firm specializing in M&A, while approvals from a national security perspective in Japan may not be a significant obstacle from a conventional perspective, there are market voices that emphasize the importance of Seven & i as a safeguard during natural disasters. If these voices become more prominent, the government may adopt a more conservative approach. Ito made these remarks on CNBC on Wednesday.

Neither Seven & i nor Couche-Tard immediately responded to requests for comments.

—CNBC's Lim Hui Jie contributed to this report.