Apple Pay now boasts more than 500 US banks thanks to latest round of additions

Some important firms in the update include Citizens Bank, E-Trade Bank, and the credit unions for MIT, Johns Hopkins, and McGraw-Hill. Many of the new issuers are highly localized, such as Austin's Amplify Federal Credit Union.

The update is Apple's first since its Sept. 9 press event. That day, Discover announced that its credit cards would be ready for Apple Pay on Sept. 16, alongside iOS 9. On Sept. 11, U.K. banks Lloyds, Halifax, and the Bank of Scotland joined the platform.

When iOS 9 debuts it will usher in other important changes, for instance renaming the Passbook app to Wallet, and implementing support for store credit and rewards cards. iPhone owners will also be able to open Wallet by double-tapping the home button when their phone is locked.

The complete list of new U.S. banks includes:

• Amplify Federal Credit Union
• Bank of the Ozarks
• Branch Banking & Trust
• Bridgehampton National Bank
• Capital Educators Federal Credit Union
• Centra Credit Union
• Charlotte Metro Credit Union
• Citizens Bank
• Coastal Federal Credit Union
• Credit Union 1
• Dollar Bank, FSB
• Eglin FCU
• E-Trade Bank
• First Community Bank
• First Community Credit Union (OR)
• First Florida Credit Union
• First National Bank of Waseca
• Floridian Bank
• Georgia United Credit Union
• Johns Hopkins Federal Credit Union
• Kennebunk Savings Bank
• Kirtland Federal Credit Union
• Leaders Credit Union
• Maine Savings Federal Credit Union
• McGraw-Hill Federal Credit Union
• Merchants Bank
• MIT Federal Credit Union
• National Penn Bank
• Navigant Credit Union
• Nodaway Valley Bank
• Nymeo
• OU Federal Credit Union
• Pacific NW Federal Credit Union
• Power Financial Credit Union
• Seaboard Federal Credit Union
• SECU of Maryland
• Southern Security FCU
• Southwest Financial Federal Credit Union
• Sterling Federal Bank
• The Cape Cod Five Cent Saving Bank
• The Focus Federal Credit Union
• Trupoint Bank
• UBI Federal Credit Union
• Vinton County National Bank
• Watertown Savings Bank
• Xceed Financial Federal Credit Union