you (honorific, business correspondence)
A formal second-person pronoun used primarily in written business correspondence to address a company or organization with respect. Not used in everyday conversation.
I sincerely wish for your company's continued success.
I am delighted to hear of your company's increasing prosperity.
Compound of 貴 (ki, 'honorable') and 台 (dai, 'platform' or 'stand'), used as a respectful term for an esteemed person or organization. The exact historical derivation is uncertain, but it follows a pattern of honorific compounds in formal written Japanese.