American Express offers some excellent churning cards, such as the 25,000 no-fee AMEX Gold Card [this is a referral], and the 60,000 AMEX Platinum card [this is a referral]. Many people will go on an “app-orama,” applying for a bunch of cards, including numerous AMEX cards, in a single day. There’s nothing wrong with this. Indeed, you can apply for as many AMEX cards you want in a single day, however, you won’t be instantly approved for all of them.
Over time, I’ve noticed that on an app-orama, the first AMEX application is generally instantly approved. The second is “conditionally approved,” and the third is “undergoing review.” Usually, all three cards are eventually sent out as approved.
I spoke with AMEX regarding a recent app-orama. What happened is I applied for the AMEX Platinum first, and was instantly approved, and the AMEX Gold second, which was conditionally approved. The agent explained to me that once an AMEX card is approved, it needs to be sent out to the customer prior to other cards being approved. So, although all your applications (assuming that you are credit-worthy) will eventually be approved, they’ll have to wait in a queue as your cards get mailed out.
Conventional wisdom is to apply for all your cards on the same day in an app-orama. I believe that wisdom holds true, UNLESS you’re applying for only AMEX cards. I’d advise that you only do one AMEX card on day one, receive that card in the mail, then apply for the second card, etc. In the end, there’s probably no difference, but I’m more comfortable with instant acceptances rather than waiting for cards to undergo a manual review.