Update: Some offers mentioned below are no longer available. View the current offers here.Large welcome bonuses offer a great opportunity to boost your account balance — as do shopping portals and bonus categories — but there’s another oft-overlooked option available with a handful of cards: referral bonuses. American Express launched a limited-time referral program in October to help cardholders maximize the card recommendations they make to friends and family. Unfortunately, the October refer-a-friend promotion is coming to an end, but you still have time to earn one of the amazing referrals.How the October refer-a-friend offers workIn many cases, it’s easy to earn thousands of bonus points or cash back. When a friend applies for a new account using your custom link, you’ll be eligible for a bonus after they’re approved. They’ll still be eligible for a welcome bonus as well, making it a win-win for you and your friend. This month, American Express is sweetening the deal even further. When your friend applies for a new account by Oct. 28, 2020, you may also be able to earn more rewards per dollar spent for the first three months after they’re approved. Be sure to see your specific offer right here for more details.For example, on my American Express® Gold Card, I’m eligible to earn 25,000 Membership Rewards points (instead of the typical 10,000), but I’ll also get an additional 3x on all spending for three months if my referral is approved. That means I’d earn 7x on U.S. supermarkets (up to $25,000 per year; then 1x) and restaurants, 6x on eligible airfare and 3x on all other purchases.Screenshot courtesy of American ExpressThis particular offer is available with the following Amex cards:Amex EveryDay® Credit Card from American ExpressAmex EveryDay® Preferred Credit Card from American ExpressBlue Cash Everyday® Card from American ExpressBlue Cash Preferred® Card from American ExpressAmerican Express Cash Magnet® CardDelta SkyMiles® Blue American Express CardDelta SkyMiles® Gold American Express CardDelta SkyMiles® Platinum American Express CardDelta SkyMiles® Reserve American Express CardThe Platinum Card® from American ExpressAmerican Express® Gold CardAmerican Express® Green CardHilton Honors American Express CardHilton Honors American Express Aspire CardMarriott Bonvoy Brilliant™ American Express® CardThe information for the Amex Cash Magnet, Amex EveryDay, Amex EveryDay Preferred, Amex Green cards has been collected independently by The Points Guy. The card details on this page have not been reviewed or provided by the card issuer.Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.After logging in here with your account information or card details, you should see options to refer a friend via email, a social media post or a direct referral link — the latter of which could be shared with your broader network to maximize your return.Screenshot courtesy of American ExpressMeanwhile, if you’re looking for a card for yourself, you can apply using the links below. Once you’re approved, you should be able to refer a friend and earn an additional bonus once they’re approved, too.Amex EveryDay® Credit Card from American ExpressAmex EveryDay® Preferred Credit Card from American ExpressBlue Cash Everyday® Card from American ExpressBlue Cash Preferred® Card from American ExpressAmerican Express Cash Magnet® CardDelta SkyMiles® Blue American Express CardDelta SkyMiles® Gold American Express CardDelta SkyMiles® Platinum American Express CardDelta SkyMiles® Reserve American Express CardThe Platinum Card® from American ExpressAmerican Express® Gold CardAmerican Express® Green CardHilton Honors American Express CardHilton Honors Aspire Card from American ExpressMarriott Bonvoy Brilliant™ American Express® CardAs a reminder, you’ll need to refer a friend using this link and your friend will need to apply for a new account by Oct. 28, 2020. Once they’re approved, you’ll be good to go!Additional reporting by Madison Blancaflor.