For the cc that I use for the business for years, I used a personal card that I didn’t use for personal use that has a 60k limit, because the consumer protection laws on personal cards are differed. Many business cards don’t have the same fraud protection. That card number was stolen every 6-12 months and used for thousands of our purchases and they never questioned anything. I also accumulated about 200k in rewards points per year that were redeemed for gift cards for employee perks since rewards aren’t taxable. When any of our corporations were new, we had to personally guarantee any new credit lines.