Is 'Yours hopefully' formal or informal?

Recently, I had to write an email to one of my professors regarding an urgent matter. I was basically asking him for some guidance in the matter.

I am not a native speaker and normally I end my formal emails with 'Best regards'. Since this was important to me and I wanted a quick response I wanted to sign with 'Your hopefully'. I didn't know if this would be an appropriate way of ending a letter to a professor.

Is 'Yours hopefully' formal or informal? Is it still used to end letters with?

Note: I have read the following posts.

Is it "Yours faithfully" or "Yours sincerely"? Is usage of “Yours sincerely” still appropriate?

Solution 1:

As far as I'm aware, "yours sincerely" and "yours faithfully" are the two formal closings with their own rules described in the article you link. I haven't come across "yours hopefully" before and whilst it can make sense, as @Lawrence says, then it could be fine to use. However, if you'd like to stick to more standard endings, I would suggest a closing sentence such as "I hope to hear from you soon" / "I hope for a resolution to this matter", followed by the more standard closings.

Another option which I recall seeing could be "Yours in anticipation".

Finally, depending on your location, there are US/UK differences to bear in mind.