Tip of the hat to Frugal Travel Guy and OP on FT..... updated 10am e.s.t. Holders of Platinum & Premier Gold personal and business cards can get 10K for each additional cardholder up to 5. On gold cards up to 5 AU's is free. On Platinum 5 Gold AU's can be added for $45 total. Must spend something on each card. Names and birthdates are required but they are strangely not requiring SS#'s immediately. AmEx is very strict about SS#'s of AU's so I wouldn't test this. Offer supposed to be good through 12/31/11 but is targeted so may have to phone a couple times to get agreeable csr. Phone Membership Rewards and mention offer code 5721 Offer 5721 also applies to the Business Premier Gold card Just call the Membership Rewards department at 1-800-AXP-EARN and mention offer code: 5721. When I called the number on the back of my card the rep could not find the offer.