Try getting a
Dunn & Bradstreet file for your company. When you do business with other companies, or if they extend credit to you, ask them to report to D&B.
^^ this.
Also, Amex is way over rated.
They have pulled off and lowered several good features of their Gold and Black cards over the years.
About the only thing left they even have worth mentioning I think is the upgrade on flights, everything else is not all that great. Is their points still 2% or did they finally lower that too? not sure if Plum has changed though.
Personally, I have found out that many other credit cards can somewhat match Amex for a lot of benefits. If your looking for a charge card where you still HAVE to train the card to even use that so called "unlimited spending" ( yeah right ) then you don't have a choice really.
If your looking for something to get upgrades, good points conversions, and other perks, then look at Chase Sapphire and a few cards from BOA.
I personally use a debit card tied to my biz bank account. I see no real need in borrowing money for 30 days and gaining a few interest points here and there and then spending time sending the credit card company the payment before the due date. When I first started out in affiliate I left a large amount of money in my interest bearing savings/checking account and it was pathetic the amount of interest it made in a month. it wasn't worth borrowing on credit to keep that money there for net 30 to gain that and then pay it back with affiliate earnings.
I'd rather it come out of my account and not worry about having to remember the due date later on. I actually get the same protection on purchases, point conversions, and less work of sending in a payment every month to a 3rd party as a charge or credit card. The only thing I might not get is upgrades on flights, but I have another card I use for that entirely anyways. If you have a good standing account, you can also get POS daily limits raised to almost 6 figures a day on the debit card as well.
Anyways, look at Chase Sapphire though for a credit card to run through biz stuff unless you just want the Ink one. If you want a high limit debit though, Chase and Citibank is where you should look. Also some financial services ( think mutual funds, retirement account ) will give you a bank account with them with high limit cards as well.