When you apply for a business card (American Express, Chase, Citi, most issuers) the inquiry appears on your credit report, but the resulting new account does not. This means that you can open American Express or Chase business cards without changing your Chase N/24 score. (However, Chase does look at your N/24 score when you apply for Chase business card. If you are already at 5/24 you could not open a Chase business card now, but you can open business cards from American Express and most other issuers.)