The yen’s rapid appreciation over the past month presents another hurdle to Alimentation Couche-Tard’s takeover proposal for Japan’s Seven & I Holdings.

A buyout by the Canadian convenience store operator, which would be the biggest-ever foreign acquisition of a Japanese company based on Seven & I’s current market capitalization, already faces questions in terms of potential funding and the target’s efforts to seek government protection.

The yen has surged about 11% since hitting multi-decade lows versus both the dollar and its Canadian counterpart in early July. Currency strategists expect the rally will continue in coming months as Japan’s interest rate gap with other nations narrows, making Seven & I increasingly expensive for the foreign suitor.