The speculation is only due to lack of information. However, even if you indeed handed the keys to the US government, you will be bound by them not to disclose

The speculation is only due to lack of information. However, even if you indeed handed the keys to the US government, you will be bound by them not to disclose it, so there's no much point answering either "yes" or "no" as long as you or any of your company assets are in the reach of US government. The same line of thought applies to any company connected with the US in any way, not just to Opera/FastMail. Anyways, thanks for the update.